Water Use in Auckland Households Auckland Water Use Study (AWUS) Final Report. Matthias Heinrich Sustainable Building Scientist

Transcription

1 EC1356 Water Use in Auckland Households Auckland Water Use Study (AWUS) Final Report Author: Matthias Heinrich Sustainable Building Scientist Reviewer: Nigel Isaacs Principal Scientist Contact: BRANZ Limited Moonshine Road Judgeford Private Bag Porirua City New Zealand Tel: Fax: Project Number: EC1356 Page 1 of 118 Pages

2 Executive summary This Executive summary provides a selection of the results, discussed within the main report. Auckland s population is growing at approximately twice the national average, and its water and wastewater infrastructure needs to keep up with the growth, to ensure a solid water supply for the future. From February 2008 until September 2008, 51 houses across the whole Auckland region have been monitored in detail to see how water is used in the residential sector. This sector is responsible for 62% of the total water used in the region or nearly 84 billion litres per year (L/year) (135 billion L in total)(watercare 2006). Two separate monitoring periods (summer and winter) were analysed, to see how water use varies throughout the year. Monitoring High resolution water meters were installed in a randomly selected sample of 51 houses. Data loggers captured flow information at 10 second intervals for the duration of the project. This detailed flow information was required to disaggregate the individual flow traces into its end use components (e.g. toilets, showers etc), using a process called Flow Trace Analysis. Apartments have not been included in the sample, because sub-metering would have been required in order to achieve the desired results. This was considered to be unfeasible at the time the project commenced. Water use On average 179 litres of water per person per day (L/p/d) were used during the summer and 175 L/p/d during winter. Indoor uses remained fairly constant throughout both monitoring periods. The main difference is the outdoor uses. Table i shows the summer and winter end use distributions. The highest water use was found to be the shower, which used just over 3 of the indoor water. The next highest indoor use was found to be the washing machine (27%), followed by the toilet ( 2 of indoor use). Table i: End use comparison (per person) ALL USES INDOOR USES End use Summer Winter Summer Winter Tap 12% 16% 15% 18% Shower 25% 3 31% 32% Washing machine 23% 24% 27% 27% Toilet 18% 19% 23% 2 Dishwasher 1% 1% 2% 1% Bathtub 2% 1% 1% 1% Misc 1% 1% TOTAL INDOOR 8 92% Outdoor 17% 6% Leaks 4% 2% TOTAL Page 2 of 118 Pages

3 Toilet Taps Washing machine Shower Daily use Gen. Table ii: Summary of results Auckland (AUK) Entity Units Summer Winter Compare Sample size Houses Ave. occupancy People Per house Average L % Median L % Stdev L % Max L % Per person Average L % Median L Stdev L % Max L % Peak demand Average L/day % Median L/day % Stdev L/day % Max L/day % Duration Average min % Median min % Stdev min Volume Average L % Median L % Stdev L % Flow Average Lpm % Median Lpm % Stdev Lpm % Frequency Average # Loads/day Average # % Stdev # % Loads/person/day Average # % Litres/day Average L % Stdev L Litres/person/day Average L Stdev L Litres/load Average L % Median L Stdev L % Duration Average sec % Median sec Stdev sec % Volume Average L % Median L Stdev L % Flow Average Lpm % Median Lpm % Stdev Lpm % Uses per day Average # % Volume/flush Average L % Median L % Stdev L % Flushes/day Average # % Median # Stdev # % Table ii shows a summary of the main results and a comparison of the two seasonal monitoring periods. The major difference between summer and winter was found to be higher peak water usage during summer, which is mainly due to outside uses, such as irrigation. Overall, it can be seen that other parameters are very similar throughout the season, which backs up the claim that indoor usage remains constant. The measured parameters for shower, washing machine and toilet use show little variation over the seasons. However many uses have a relative high standard deviation, which shows that water usage behaviours can be very different from house to house. Showers On average each person showers 0.9 times a day for 6.6 min in summer and 7 min during winter, with a shower flow rate of around 8 litres per minute (Lpm). Showers have been ranked according to the Water Efficiency Labelling Scheme (WELS) star rating and it was found that the majority of showers are already in the high efficiency categories. Sixty-five percent would receive a 3 star rating or higher - 3 stars is current maximum in shower category (also see Figure 84). Colour Legend 9-11 Range 8-9 ; < 8 ; > 12 Page 3 of 118 Pages

4 Washing machine Each person in the study would wash 0.35 loads per day on average, using around 122 litres/load (L/load) (max 190 L/load). Replacing existing washing machines with more efficient models could have a large effect on the overall water usage and wastewater volumes. This is further discussed in section 8.2. Indoor taps Indoor taps were found to be used efficiently already, as most tap use events received high efficiency ratings (6 star WELS rating). Even if a tap is capable of higher flows, data suggest that it is not necessarily used in this way. It is considered flow restrictors would only have a minimal effect in reducing overall water usage. Toilets The toilet in the home is flushed just under five times per person per day, using an average of 6.7 litres/flush (L/flush). When ranking toilet volumes according to the WELS rating, it was found that the majority of currently installed models would fail to obtain a star rating (i.e. 0 stars). The toilet was one of the areas where high overall water savings can be achieved should all toilet models within Auckland be upgraded to a much higher efficiency standard. Outdoor use Seasonal variation is the main driver for outside usage. During summer, outdoor use represented 17% of the total uses, whereas during winter this proportion dropped to 6%. Similar to leaks, there are only a small number of households responsible for the majority of outside uses in both summer and winter. The highest outside users in the study group were the two houses which had swimming pools and spa pools. Irrigation was the highest single outdoor usage, and these events had a large effect in increasing a household s daily peak demand. The houses with a high outdoor usage during summer were also responsible for high outdoor usage during winter. Leaks Leaks can have a major impact on an individual home s water use if undetected or left ignored. During April, one home had leaks which totalled 200,000 L during this month. This was not the only case, as leaks have appeared in several homes. It is necessary to minimise leaks as there are large water-saving potentials. Similarities with WEEP The data of this study showed remarkable similarities to the data collected from the 12 WEEP houses on the Kapiti Coast (see section 7). The main difference between the two is a slightly higher summer outdoor usage on the Kapiti Coast. Indoor uses follow a similar pattern for both summer and winter periods of each study, even though there was an 18 month gap between the two studies and the relatively small sample size of WEEP. Does this imply that there are similar water use patterns throughout New Zealand? A more geographically representative study would be required to answer this question. Page 4 of 118 Pages

5 Author Water Use in Auckland Households Auckland Water Use Study (AWUS) Final Report Matthias Heinrich (BRANZ Ltd) Reference Heinrich M Water Use in Auckland Households: Auckland Water Use Study (AWUS) Final Report. BRANZ Ltd, Judgeford, New Zealand. Client Watercare Services Ltd 2 Nuffield Street Newmarket Auckland 1023 New Zealand Acknowledgements BRANZ would like to thank the numerous staff involved in this project at Watercare, Metrowater, Manukau Water, North Shore City Council, Ecowater, Rodney District Council and United Water for the time and effort they gave to ensure a successful outcome. In particular, I would like to acknowledge the staff who facilitated the meter installation phase of the project in each of the Local Network Operators (LNOs), as it is recognised that this was a difficult process to co-ordinate, and also members of the Water Advisory Group for their help in getting the project started. I would also like to take the opportunity to thank individual BRANZ staff and subcontractors who made valuable contributions to this project, especially Norm Wood, Andrew Pollard, Luca Quaglia, Chun-Chiu Lee, Nigel Isaacs, Judith Steedman, and everyone in the 51 households, without whom this research would have not been possible. Page 5 of 118 Pages

6 Contents Page 1. INTRODUCTION Why conduct the project? Report structure SITE SELECTION Occupancy rates House information DATA COLLECTION AND MONITORING Water meter installation Data logger installation and audits Monitoring Equipment High resolution water meter Data logger Waterproofing Downloading data Analysis SUMMER MONITORING PERIOD Volume usage analysis summer monitoring period Total daily use Daily per capita use Peak daily demand End use analysis February End uses per household End uses per person End use adjustment Shower Washing machines Indoor taps Toilet Leaks Outdoor use and irrigation Dishwasher End use analysis March End uses per household (March 2008) End uses per person End use adjustments End use analysis summer monitoring period Shower Washing machine Number of loads Page 6 of 118 Pages

7 4.4.3 Indoor taps Toilet Leaks Outdoor Daily profiles summer period WINTER MONITORING PERIOD End use analysis winter End uses per household End uses per person Volumetric end uses Shower Washing machines Indoor taps Toilet Leaks Outdoor use and irrigation Dishwasher SUMMER / WINTER MONITORING PERIOD COMPARISON Volume usage comparison summer and winter period Total daily use Daily per capita use Peak daily demand End use analysis summer and winter comparison Shower Washing machine Number of loads Indoor taps Toilet Leaks Summer leaks Winter leaks Outdoor Daily profiles COMPARISON BETWEEN AUCKLAND STUDY AND WEEP APPLIANCE UPGRADE Toilet savings Washing machine savings Shower savings Indoor tap savings Greywater DISCUSSION AND CONCLUSIONS Page 7 of 118 Pages

8 9.1 Key results Next steps Last words REFERENCES APPENDIX A EQUIPMENT APPENDIX B SAMPLE FLOW TRACE APPENDIX C FLOW BANDS APPENDIX D MAILOUT INFORMATION APPENDIX E QUESTIONAIRE APPENDIX F LIST OF ABBREVIATIONS Figures Page Figure 1: Report structure Figure 2: Occupancy rate Figure 3: Monitoring set up Figure 4: Distribution of total water use per household per day Figure 5: Distribution of total water use per person per day Figure 6: Daily household peak demand Figure 7: Daily per person peak demand Figure 8: Total end uses per household February period Figure 9: Total end uses per household (no leaks) February period Figure 10: Indoor end uses per household February period Figure 11: Total end uses per person February period Figure 12: Total end uses per person (no leaks) February period Figure 13: Indoor end uses per person February period Figure 14: Total end uses per household (excluding major leakage home) Figure 15: Total end uses per person (excluding major leakage home) Figure 16: Shower duration Figure 17: Shower volume distribution Figure 18: Shower flow rates Figure 19: WELS star rating Figure 20: Washing machine average load volumes Figure 21: Tap use duration Figure 22: Tap use volumes Figure 23: Tap flow rate distribution Figure 24: WELS star rating (taps in litres per minute) Figure 25: Average toilet flushes per person per day Figure 26: Toilet flush volumes Figure 27: WELS star rating (toilets all flushes) Figure 28: WELS star rating (toilets by house) Figure 29: Outdoor usage Figure 30: Total end uses per household March period Figure 31: Total end uses per household (no leaks) March period Figure 32: Indoor end uses per household March period Figure 33: Total end uses per person March period Page 8 of 118 Pages

9 Figure 34: Total end uses per person (no leaks) March period Figure 35: Indoor end uses per person March period Figure 36: Household end use distribution (excluding major leakage home) Figure 37: Per person end use distribution (excluding major leakage home) Figure 38: Shower duration summer monitoring period Figure 39: Shower volumes summer monitoring period Figure 40: Shower flow rates summer monitoring period Figure 41: Shower flow efficiencies according to WELS Figure 42: Shower flows according to hot water system Figure 43: Average number of showers per person per day Figure 44: Average washing machine volumes per load Figure 45: Relationship between household size and average number of loads Figure 46: Relationship between household size and average number of loads Figure 47: Indoor tap use duration summer monitoring period Figure 48: Indoor tap use volumes summer monitoring period Figure 49: Indoor tap use flow rates summer monitoring period Figure 50: Individual tap flows ranked according to WELS Figure 51: Toilet flush volume distribution summer monitoring period Figure 52: Average toilet flushes per person per day Figure 53: WELS star rating (toilets by house) Figure 54: Share of total leakage Figure 55: Outdoor water usage Figure 56: Average daily flow profile (10 min time steps) Figure 57: Average weekday/weekend profiles (10 min time steps) Figure 58: Total end uses per household winter period Figure 59: Total end uses per household (no leaks) winter period Figure 60: Indoor end uses per household winter period Figure 61: Total end uses per person winter period Figure 62: Total end uses per person (no leaks) winter period Figure 63: Indoor end uses per person winter period Figure 64: Shower duration Figure 65: Shower volume distribution Figure 66: Shower flow rates Figure 67: WELS star rating Figure 68: Washing machine average load volumes Figure 69: Tap use duration Figure 70: Tap use volumes Figure 71: Tap flow rate distribution Figure 72: WELS star rating (taps in litres per minute) Figure 73: Average toilet flushes per person per day Figure 74: Toilet flush volumes Figure 75: WELS star rating (toilets all individual flushes) Figure 76: WELS star rating (toilets by house) Figure 77: Distribution of litres per household per day Figure 78: Distribution of litres per person per day Figure 79: Daily household peak demand Figure 80: Daily per person peak demand Figure 81: Shower duration summer / winter comparison Figure 82: Shower volumes summer / winter comparison Figure 83: Shower flow rates summer / winter comparison Figure 84: Shower flow rates according to WELS Figure 85: Average number of showers per person per day Page 9 of 118 Pages

10 Figure 86: Average washing machine volumes per load Figure 87: Relationship between household size and average number of loads Figure 88: Relationship between household size and average number of loads (plotting each house individually) Figure 89: Indoor tap use duration summer monitoring period Figure 90: Indoor tap use volumes summer monitoring period Figure 91: Indoor tap use flow rates summer monitoring period Figure 92: Individual tap flows ranked according to WELS Figure 93: Toilet flush volume distribution summer monitoring period Figure 94: Average toilet flushes per person per day Figure 95: WELS star rating (toilets by house) Figure 96: Average daily flow profile summer / winter (10 min averages) Figure 97: Average weekday profiles summer / winter (10 min averages) Figure 98: Average weekend profiles summer / winter (10 min averages) Figure 99: Toilet retrofits water savings Figure 100: Washing machine retrofits water savings Figure 101: Water flows in litres/hour Tables Page Table 1: Monitored homes Table 2: Customer reply rates Table 3: Extract of sample output Table 4: Comparison of indoor uses Table 5: Average volume per end use Table 6: Summary of washing machine use Table 7: Total end use comparison (adjusted values) Table 8: Indoor end use comparison Table 9: Tap use summary Table 10: Comparison of winter indoor uses Table 11: Average volume per end use during winter period Table 12: Summary of washing machine use Table 13: Winter end use comparison (per person) Table 14: Washing machine summary Table 15: Tap use summary Table 16: Total end use comparison (per person) Table 17: Indoor end use comparison (per person) Table 18: Summary comparison WEEP / Auckland Table 19: Toilet information Table 20: End use flow distribution (litres per hour) Page 10 of 118 Pages

11 1. INTRODUCTION During the 2007 financial year, more than 136 billion L of A-grade drinking water were supplied and over 104 billion L of wastewater were treated by WaterCare Services Limited, who supply bulk water and wastewater services to the Auckland region. BRANZ has been contracted by Watercare to conduct an end use study on their behalf to find out where the water is used in Auckland homes. Watercare draws the water from 12 sources, treats it to A-grade drinking water, and supplies it to six Local Network Operators (LNOs). It is then on-sold to more than 1.2 million consumers (WaterCare 2006). For the study, 51 houses from throughout the Auckland region were randomly selected. As each LNO supplies water to a different number of customers, the sample was adjusted accordingly. The largest population is served by Metrowater (Auckland City), where 18 houses were selected. The distribution is shown in Table Why conduct the project? Reducing the amount of water that is taken out of the system delays the need for finding new sources of water and for infrastructure expansion, which both carry high costs. Auckland s population has grown at approximately double the national average over the last five years. As a result, water demand has increased along with the amount of wastewater that needs to be treated. Eventually a point is reached where the available water sources become completely allocated, and can not supply the necessary amount of water. Either a new source needs to be found and connected to the infrastructure system, or the total amount of water used needs be reduced. By reducing water use, expensive infrastructure expansions can be shifted further into the future. A demand forecast is developed annually by Watercare to predict the future demand requirements for the water networks in the Auckland region, and to plan for future investments in the infrastructure. This is where residential end use analysis comes in, since the more that is known about a specific sector, the more accurate the forecasts can become. Also by getting a better understanding of where the water is used in the homes, opportunities for improving water efficiency can be identified and monitored for their effectiveness. This study builds upon the expertise gained in the Water End Use and Efficiency Project (WEEP) (Heinrich 2007), which was a pilot study monitoring water end uses in a sample of 12 houses on the Kapiti Coast. Data collection and handling processes have been improved since then to handle the larger sample. The conceptual basis also dates back to experience made in the Household Energy End use Project HEEP (Isaacs et al 2006), a 10 year energy study looking at energy usage in over 400 New Zealand homes. 1.2 Report structure This final report is based on the findings of the whole study period (February 2008 until August 2008) and builds upon the interim report, which was produced for the summer monitoring period (Heinrich 2008a). Figure 1 shows the basic structure of this report. The summer monitoring period consisted of two separate and independent months of monitoring (February and March). This approach was used to see if water usage variations exist within a season. After finding that usage remained fairly constant over Page 11 of 118 Pages

12 summer on both a house level and overall sample level, the winter data consists of only one set of measurements (June/July). This interval is still sufficient, as other similar studies have monitored on an end use level of only two weeks (Heinrich 2006). However detailed flow information was collected from February up until September, as the equipment was still in place. This data can be used for future studies. Part 1 Background (Sections 1 3) Part 2 Summer monitoring period (Section 4) Material covered in interim report Part 3 Winter monitoring period (Section 5) Part 4 Compare: summer & winter (Section 6) Part 5 Compare: Auckland & WEEP (Section 7) Part 6 Conclusions & Discussions (Sections 8 9) Figure 1: Report structure 2. SITE SELECTION To obtain a balanced sample distribution to represent the Auckland region, each district had a different number of houses monitored as the population and water volumes within these districts varied. It was decided to monitor 50 houses initially, spread across the six LNO regions. This increased to 51 houses, after the sample was weighted for each of the regions. The Metrowater (central Auckland) district has the highest population, so 18 homes were monitored in this area. Table 1 shows the sample size. Houses were then selected at random from the metering databases of the individual LNOs. A 1 reply rate was assumed, so 10 times as many homes were initially selected as required from each of the districts. Overall 546 information packs were sent out to the randomly selected customers. These packs were customised to suit the needs of each of the six LNOs, and included the following documents: covering letter explaining the study and its aims Table 1: Monitored homes Area Local Network Operator (LNO) Monitored homes Manukau Manukau Water 12 Central AUK Metrowater 18 North Shore North Shore CC 9 Rodney Rodney DC 2 Papakura United Water 2 Waitakere Ecowater 8 Total 51 Page 12 of 118 Pages

13 Relative frequency reply form with a short questionnaire to secure participation and get an idea of what water-using appliances are found in the home, together with contact details frequently asked questions about the survey and study document explaining the data collection procedure in more detail. Table 2 shows the number of replies that have been received and the reply rates. Table 2: Customer reply rates REPLIES REPLIES Area Monitored homes Positive Negative Total letters % Yes % No % Reply Manukau Central AKL North Shore Rodney Papakura Waitakere Total Average (%) Occupancy rates Figure 2 shows a distribution of the number of occupants in the study group (51 homes in total). The average occupancy was found to be 2.7 occupants per home, which is slightly lower than census figures published by Statistics NZ (Statistics NZ 2006) of 2.9 people per dwelling. The largest group were the two person households, which represents 47% of the total sample. The largest number in any household was found to be eight people. Single occupancy households represented 14% of the group Average = 2.7 people Median = 2 people Std deviation = 1.5 people Number of homes within category Number of Occupants Figure 2: Occupancy rate Page 13 of 118 Pages

14 2.2 House information The study group includes houses from varying demographic groups (income, education, age, ethnicity and others) and household sizes. Some houses would have no outside water uses (only indoor), whereas others used water for irrigation, or filling swimming pools and spa pools (two houses had swimming pools). One home had a broken pipe through the majority of the summer monitoring period, which made up most of this home s total uses. Some end uses were found in each house, such as toilets, showers and taps. Washing machines, dishwashers, baths and other end uses were not found in all homes. These characteristics are also discussed in the relative end use sections. Multi-residential buildings such as apartment blocks have not been included in this study. 3. DATA COLLECTION AND MONITORING This section focuses on how the data was collected and the type of equipment that has been used in the study. A more detailed description of the methodology and technology can be found in BRANZ Study Report 159 Water End Use and Efficiency Project (WEEP) Monitoring Report (Heinrich 2007). 3.1 Water meter installation After the reply forms had been received and sorted, the properties were inspected by the LNOs to look at the feasibility of the water meter installations. The LNOs required that there should be no interference with the metering processes, so instead of replacing the existing meters the high resolution water meters were installed in series to the existing water meters. Only Manukau Water replaced the existing meters. Not all the installations were straightforward, especially in central Auckland, due to concrete driveways, space restriction or other factors. Figure 3 shows a photo of the set up of an installation. Metering box Waterproof box containing data logger Harness Water meter Lid Figure 3: Monitoring set up Page 14 of 118 Pages

15 3.2 Data logger installation and audits Once the water meters were installed house visits were conducted to: install the data loggers; calibrate the equipment; record which water-using appliances were in the house; and conduct a questionnaire on water-using behaviour and occupant demographics. The questionnaire data is also a helpful tool for analysing the individual flow traces, as it provides a better picture of how water is used. 3.3 Monitoring To analyse the individual water end uses from a single high resolution water meter, a method called Flow Trace Analysis has been used, which was used in WEEP. High resolution flow data from the attached water meter, which has a resolution of over 34 pulses per litre (ppl), was logged at a 10 second interval using BRANZ data loggers. This high level of detail is necessary to produce the accurate flow traces, which can then be analysed using a specialised software package to break the flow traces into its individual end use components. See Appendix B for an example. 3.4 Equipment Two main pieces of equipment are required to collect the raw flow information from each of the houses (see Appendix A for data sheets) High resolution water meter The electronically modified nutating disk meter (MES25 Neptune) provides a pulse output (reed switch), which can be picked up by a data logger. These high resolution meters produce a pulse output of 34.2 ppl, to ensure the collection of detailed flow traces Data logger The in-house developed BRANZ data loggers (84 Series USB) are directly connected to the output of the water meter to collect flow profiles at a 10 second interval. At this recording interval, the storage capacity is around 35 days ( 300,000 individual records). Each month the data loggers were replaced and downloaded, to obtain a continuous flow profile over the whole monitoring period. The data loggers were modified since WEEP to increase the download speed significantly, as this was critical due to the large number of houses involved Waterproofing The waterproofing of the installation was an important issue which was addressed. The loggers have relatively high costs and loss of equipment and data should be kept to a minimum (and if possible completely avoided). Airtight lunch boxes with a clip-on lid were used as a container for the logger. A cable gland was fitted and sealed for the cable from the water meter which connects to the data logger. To reduce the amount of condensation, desiccant was added to the box which contained the logger, and this further reduced the moisture content within the box. When the logger was downloaded, the used desiccant was then replaced by a dry package. The logger would sit in the metering box together with the water meter, which is a wet and damp environment, with some boxes tending to flood completely. For this reason the logger was installed as high as possible in case the metering box filled up with water. Even though the box containing the logger was sealed, water needs to be kept Page 15 of 118 Pages

16 away as much as possible. One way to ensure this is to have the logger placed directly under the lid of the metering box, kept in place by a harness (shock cord). 3.5 Downloading data Every month, the data loggers were replaced and downloaded by our download person. The raw data files were then sent to BRANZ for further processing. At this stage the files are in no format to be analysed, as the file only contains a row of numbers, representing the flows. The reason for this is to maximise the storage capacity of the loggers by only storing necessary information. The raw files need to be treated by applying meter constants, date/time information and flow information (transformed into a certain format), in order for them to be recognised for further analysis. This step also identifies whether there is a problem with data integrity and if further action needs to be taken. 3.6 Analysis Each flow trace is analysed using the TraceWizard (Aquacraft) software package to disaggregate it into its individual components. Detailed information on each individual event (e.g. toilet flush) is obtained in this step, which is shown in Table 3. Table 3: Extract of sample output ID Name Date Start time Duration End time Peak Volume Mode ModeFreq 0 Toilet 1 16/11/ :04:50 a.m :05:50 a.m Toilet 2 16/11/ :43:50 a.m :44:20 a.m Faucet 1 16/11/2006 3:21:40 p.m. 10 3:21:50 p.m Dishwasher 1 16/11/2006 5:22:40 p.m. 70 5:23:50 p.m Using this high level information from the individual houses, the next stage is to combine the information, which is stored in an MS Access database, and extract the required information. 4. SUMMER MONITORING PERIOD The summer monitoring period is split into two separate months, February and March respectively, to see if water use variations occur within the same season. A comparison between the two separate months was also conducted and can be found in this chapter. Data loggers were installed in stages, with the first loggers in place on 24 January, and a complete installation of all 51 houses carried out by 9 February. The summer monitoring period refers to the months of February and March. 4.1 Volume usage analysis summer monitoring period There is a wide variation in volumetric water uses in each of the homes. This section looks at the daily household uses, daily per capita, and daily peak uses Total daily use The average daily use per household during February 2008 was 456 L, with an average of 2.7 people living in each home. The daily volumes in Figure 4 do not include the water use from the home with the broken pipe, which would bring up the average household use for February to 523 L. Higher water uses were measured Page 16 of 118 Pages

17 Relative frequency Cumulative frequency during February than during March, due to a higher proportion of outdoor uses and the dry conditions which occurred during this period. The highest household summer use on any single day was 7,200 L. Eighty-one percent of daily uses during February were between 80 and 680 L. Seven percent of daily uses during February were 1,000 L and more, whereas during March this proportion was only 5% % 9 8% 8 7% Summer February 08 March 08 Average (L/d) % 5% Median (L/d) StDev (L/d) Max (L/d) % 3% 2% 1% February March All February March All Litres/day Figure 4: Distribution of total water use per household per day Daily per capita use The average daily per capita use for February 2008 was found to be 188 L. These daily uses do not include the figures for the home with the broken pipe, otherwise per capita usage would have increased to 262 L per day during February. As can be seen from the distribution in Figure 5, 82% of the water uses during February are between 60 and 280 litres per person per day (L/p/d). Ten percent of daily water uses per person during February are above 340 L (9% for March). The highest daily usage was 3,481 L per person. Page 17 of 118 Pages

18 Relative frequency Cumulative frequency 12% 1 8% 6% 4% 2% All February 08 February March All February March All March 08 Average (L/p/d) Median (L/p/d) StDev (L/p/d) Max (L/p/d) Litres/person/day Peak daily demand Figure 5: Distribution of total water use per person per day Figure 6 shows the daily peak water demand from each of the households (highest daily usage during particular interval). The average peak demand was 1,649 litres per day (L/d) (median 938 L/d) over the whole summer monitoring period (not average values of February and March, but maximum daily values over the whole period). The highest single day use across the whole study group was 7,200 L/d, which was mainly due to outside water usage. Seventy-nine percent of daily peak uses were below 2,000 L/d. The per person peak demand is shown in Figure 7, averaging at 683 L/p/d over the summer period (median 427 L/p/d). The highest daily use during the summer period was 3,480 L/p/d, which was recorded during February. During the March period the highest daily use was only 1,564 L/p/d. Seventy-four percent of daily peak uses for the summer were below 800 L/p/d. Seventy-nine percent of February peak uses and 85% of March uses were below 800 L/p/d. Page 18 of 118 Pages

19 Relative Frequency Relative frequency All February 08 March 08 Average (L/d) Median (L/d) StDev (L/d) Max (L/d) February March ALL < Litres/day Figure 6: Daily household peak demand 3 25% 2 15% 1 5% All February 08 February March ALL March 08 Average (L/p/d) Median (L/p/d) StDev (L/p/d) Max (L/p/d) < Litres/person/day Figure 7: Daily per person peak demand Page 19 of 118 Pages

20 4.2 End use analysis February 2008 This section looks purely at the data that was collected during the February period. From the 51 house sample, data was lost from five houses ( 1) during this period. As the data loggers are downloaded once a month, data loss can not be identified earlier. Causes of data loss: malfunctioning water meter components (heads), due to flooding of meter boxes data logger breakdown, due to faulty soldering in the manufacturing process faulty connections between logger and water meter human error. These issues have been addressed and remediation steps have been taken accordingly. This has improved the data integrity during the winter monitoring period End uses per household The following graphs (Figure 8 to Figure 10) show the measured end uses for February 2008 on a household level. These are average values over the whole study group, and not every home has a dishwasher, washing machine or bathtub. Leaks 12.6% Tap 10.4% OUTDOOR 16% Shower 22.6% Misc 0.6% Bathtub 1.7% Dishwasher 1.1% Toilet 15.3% Washing machine 19.3% Figure 8: Total end uses per household February period Page 20 of 118 Pages

21 Misc 0.7% OUTDOOR 18.7% Tap 11.9% Bathtub 2. Dishwasher 1.3% Toilet 17.5% Shower 25.9% Washing machine 22.1% Figure 9: Total end uses per household (no leaks) February period Dishwasher 1.6% Bathtub 2.4% Misc 0.8% Tap 14.6% Toilet 21.6% Shower 31.8% Washing machine 27.2% Figure 10: Indoor end uses per household February period Page 21 of 118 Pages

22 The largest measured indoor event was the shower, accounting for 32% of all indoor uses, followed by the washing machine and toilet with 27% and 22% respectively End uses per person The following graphs (Figure 11 to Figure 13) show the measured end uses for February 2008 on a per person basis. These are average values, as not every home has a dishwasher, washing machine or bathtub. The individual end uses will be discussed in the relevant sections. Leaks 23.9% Tap 9.3% Shower 19.2% OUTDOOR 13% Bathtub 1.1% Misc 0.3% Dishwasher 0.9% Toilet 14.5% Washing machine 17.6% Figure 11: Total end uses per person February period Page 22 of 118 Pages

23 Bathtub 1.5% OUTDOOR 17.2% Misc 0.4% Tap 12.2% Dishwasher 1.2% Shower 25.2% Toilet 19.1% Washing machine 23.1% Figure 12: Total end uses per person (no leaks) February period Dishwasher 1.5% Toilet 23. Bathtub 1.8% Misc 0.5% Tap 14.7% Shower 30.5% Washing machine 27.9% Figure 13: Indoor end uses per person February period Page 23 of 118 Pages

24 The largest measured indoor event was the shower, accounting for 31% of all indoor uses, followed by the washing machine and the toilet with 28% and 23% respectively. These values are comparable when looking at the summer monitoring data from WEEP (Table 4), suggesting similar behaviour in indoor water usage End use adjustment Table 4: Comparison of indoor uses Auckland WEEP Tap 14.7% 15.9% Shower 30.5% 29.5% Washing machine 27.9% 27.3% Toilet 23.1% 23.1% Dishwasher 1.5% 1.7% Bathtub 1.8% 2.1% Misc 0.5% 0. TOTAL As already mentioned, one of the homes had a major leak, which was the main reason for the high overall proportion in this category. Figure 14 and Figure 15 show the end use distributions excluding the end use results from this particular property. OUTDOOR 18% Leaks 3.2% Tap 11.4% Bathtub 1.9% Misc 0.6% Shower 25.1% Dishwasher 1.3% Toilet 16.6% Washing machine 21.5% Figure 14: Total end uses per household (excluding major leakage home) Page 24 of 118 Pages

25 OUTDOOR 17% Leaks 4. Tap 11.5% Bathtub 1.5% Misc 0.4% Dishwasher 1.2% Shower 24.4% Toilet 17.6% Washing machine 22.5% Figure 15: Total end uses per person (excluding major leakage home) Table 5 shows a summary of the share of end uses and the average volumes used per home and per person. The daily indoor demand during February for Auckland was 150 L/p/d (358 L/d), which is comparable to volumes measured in WEEP (153 L/p/d). The main difference between the Auckland measurements and WEEP are the outside uses, which are 5% lower in Auckland. Otherwise indoor uses and leaks produce similar results in both cases. Table 5: Average volume per end use Auckland (February) Auckland (February) WEEP (Summer) per household per person per person INDOOR % L/d % L/p/d % L/p/d Tap Shower Washing machine Toilet Dishwasher Bathtub Misc TOTAL INDOOR Outdoor Leaks TOTAL USE Page 25 of 118 Pages

26 Relative Frequency Shower The shower was found to be the highest water use, accounting for 31% of indoor uses (on a per person basis) during the February monitoring period. 16% 14% 12% 1 8% 6% 4% 2% Average = 6.5 minutes Median = 5.5 minutes Std deviation = 4.5 minutes Minutes Figure 16: Shower duration A total of 3,193 shower events were recorded for the study group within this period. The average shower time was 6.5 min at an average flow rate of 7.8 Lpm. The average volume for each shower event was 47.8 L. On average each person in the study group had 0.9 showers per day (2.5 showers per house per day). From the graph in Figure 16 it can be seen that 8 of the showers have a duration of 2 9 min. Only 11% are longer than 12 min and only 6% are 2 min or less. The median was 5.5 min, with the average being 6.5 min, and a standard deviation of 4.5 min. Figure 17 shows the distribution of shower volumes. Ninety percent of the showers used 90 L of water or less per event. The median was 38 L, the average volume was 48 L, and the standard deviation was calculated to be 39 L. The largest volume used by a single shower event was 371 L. One home had a shower flow rate of under 3 Lpm and, due to the large size of the family, showers of 1 min duration (3 L total volume) were not uncommon. Page 26 of 118 Pages

27 Relative frequency 2 18% 16% 14% 12% 1 8% 6% 4% 2% Average = 47.8 L Median = 38.1 L Std deviation = 38.7 L Litres Figure 17: Shower volume distribution The shower flow rates have a median of 7.4 Lpm, an average of 7.8 Lpm, and a standard deviation of 3.4 Lpm. The lowest flow rate was found to be 2.3 Lpm and the maximum average flow for any shower event was 21.4 Lpm. The distribution in Figure 18 shows that 81% of shower events had a flow rate of between 4 and 12 Lpm. Only 0.8% of showers had a flow rate of more than 16 Lpm, which specifies a 0 star rating under the proposed WELS for New Zealand (Figure 19). The maximum star rating for showers under WELS (MCA 2007) is currently 3 stars. Due to the large proportion of 3 star rated shower flows in this study, a re-examination of the WELS flow bands might need to be considered to achieve the anticipated watersaving results. If less than only 1% of shower flows do not obtain a star rating, there will be no incentive for improving efficiencies. This will be further examined once the winter data has been collected. Page 27 of 118 Pages

28 Relative frequency Frequency 14% 12% 1 8% 6% 4% 2% Average = 7.8 Lpm Median = 7.4 Lpm Std deviation = 3.4 Lpm Litres per minute Figure 18: Shower flow rates 6 Less than 7.5 Lpm than 7.5 not more than 9 than 9 not more than 12 than 12 not more than 16 than 16 Lpm % % 14.9% 12.1% 0.8% above 3 Stars 3 Stars 2 Stars 1 Star 0 Stars WELS Star rating Figure 19: WELS star rating Page 28 of 118 Pages

29 below Above 190 Relative frequency (%) Washing machines The washing machine accounts for 28% of indoor uses (on a per person basis). Ninety-four percent of the washing machines in the study group were top-loading machines, which compares with observations made in HEEP (Pollard 2007) (96%). The average load for the study group was measured to be 125 L, with Table 6: Summary of washing machine use Average Standard deviation Litres/load Loads/house/day Loads/person/day Litres/house/day (98.5) 64.7 Litres/person/day 45.6 (42.5) 28.6 an average of 0.9 loads being washed per house per day (0.4 loads per person per day). One home had no washing machine, and another only did hand washing (even though they had a washing machine). One home used rainwater for the washing machine when this was available. Across the whole group (including homes without a washing machine) 99 L of water were used for the washing machine daily (108 L on average excluding homes without a washing machine). Table 6 summarises this data. Figure 20 shows the distribution of average washing machine volumes across the study homes. Only 14% of washing machines in the study group use an average of 100 L or less per load. Sixteen percent use more than 150 L per load. 25% % % 2 1 Litres/Load Figure 20: Washing machine average load volumes Page 29 of 118 Pages

30 Relative frequency Indoor taps Indoor tap use (hot, cold and mixed) accounts for 15% of indoor uses. A total of 77,971 individual tap uses were registered during the February monitoring period. A tap use event has a distinctive start and finish. If both hot and cold water taps are used simultaneously, it is still defined as one event. On average, taps would be used 24 times per person per day. The distribution in Figure 21 shows that 75% of tap uses are 20 seconds or less. Since the data was collected at a 10 second interval, a further breakdown in data would require a shorter logging interval (e.g. 5 seconds). The average tap use time is 25 seconds, with a median of 20 seconds, and a standard deviation of 37 seconds. 5 45% 4 35% 3 25% 2 15% 1 5% Average = 25 seconds Median = 20 seconds Std deviation = 37 seconds Seconds Figure 21: Tap use duration The following distribution in Figure 22 shows the total volumes used in each tap event. Seventy-five percent of tap use events use 1 L or less and only 9.5% use more than 2.5 L. The average volume of each event is 0.9 L, the median 0.4 L, and the standard deviation 1.6 L. The distribution of tap flow rates is shown in Figure 23. Eighty-two percent of tap usage has a flow of less than 4.5 Lpm (6 star WELS rating). The average flow rate of a tap event is 2.6 Lpm, the median 1.8 Lpm and the standard deviation 2.5 Lpm. Most older homes in New Zealand have two taps (hot and cold) instead of a single mixer tap. Do these homes behave differently? This data was not recorded in the initial audit, but this theory could be examined in the future. Page 30 of 118 Pages

31 Relative frequency Relative frequency % % Average = 0.9 L Median = 0.4 L Std deviation = 1.6 L % 4 1 5% Litres Figure 22: Tap use volumes 35% % 2 15% Average = 2.6 Lpm Median = 1.8 Lpm Std deviation = 2.5 Lpm % 2 1 Litres per minute Figure 23: Tap flow rate distribution Page 31 of 118 Pages

32 Relative frequency Figure 24 shows the measured tap flow rates and ranks them according to the proposed WELS star rating, which shows that the majority of tap uses have a high star rating. Even if the taps might be capable of higher flow rates, this does not necessarily mean that taps get used at these maximum flows. One reason for this could be due to restrictions of the basin, which might only handle lower flows. For example, higher tap flows can cause the water to spray onto the floor or surroundings, due to higher impact energies. This is an important finding, as reducing the flow rates of taps might not yield the desired results. To confirm this finding, any future questionnaires need to include questions on individual tap use behaviour Less than 4.5 Lpm 82. than 4.5 not more than 6 8.4% than 6 not more than 7.5 than 7.5 not more than % 2.2% 0.7% 0.1% 6 star 5 star 4 star 3 star 2 star 1 star No star WELS Star Rating than 9 not more than 12 than 12 not more than 16 than 16 Lpm Figure 24: WELS star rating (taps in litres per minute) Toilet The toilet accounted for 23% of indoor uses (on a per person basis). A total of 16,069 individual toilet flushes were recorded from all the homes during the February monitoring period. On average 12.3 toilet flushes per home per day were recorded, with an average of 5.2 flushes per person per day (Figure 25). The average flush volume across the study homes was 6.5 L, the median 6.4 L and the standard deviation 2.6 L. A number of homes still have 12 L single flush toilets or larger (Figure 26). However toilets can be responsible for a large proportion of leaks, hence major savings can be achieved by fixing these (e.g. changing seals). This is confirmed by the flow trace analysis methodology, as leaks can be seen visually. If a toilet valve does not shut off properly, then the flow profile continues. An example of this is included in Appendix B. Page 32 of 118 Pages

33 < Frequency > 15 Relative Frequency 18% 16% 14% 12% 1 8% 6% 4% 2% Average = 5.2 Flushes Median = 4.5 Flushes Std deviation = 3.4 Flushes Number of flushes / person / day Figure 25: Average toilet flushes per person per day 12% 1 8% 6% 4% 2% Average = 6.5 L Median = 6.4 L Std deviation = 2.6 L Litres Figure 26: Toilet flush volumes Page 33 of 118 Pages

34 Relative frequency Relative frequency (%) In the analysis toilet use was not distinguished between half and full flush, but when plotting the toilet events, 62% of flushes were above 5.5 L (0 stars). Overall 80 toilets were installed in the 51 homes, of which 28% were single flush. Thirty percent of homes still had at least one single flush toilet, which used up to 12 L per flush. 7 6 Not more than 2.5 L than 2.5 not more than 3 than 3 not more than 3.5 than 3.5 not more than 4 than 4 not more than 4.5 than 4.5 not more than 5.5 than 5.5 L 61.6% % 10.3% 7.1% 2.8% 3.5% 4.9% 6 stars 5 stars 4 stars 3 stars 2 stars 1 stars 0 stars WELS Star rating Figure 27: WELS star rating (toilets all flushes) Not more than 2.5 L than 2.5 not more than 3 than 3 not more than 3.5 than 3.5 not more than 4 2.2% 4.3% 19.6% 73.9% 6 stars 5 stars 4 stars 3 stars 2 stars 1 star 0 stars WELS star rating than 4 not more than 4.5 than 4.5 not more than 5.5 than 5.5 L Page 34 of 118 Pages

35 Litres/day % of total use Leaks Figure 28: WELS star rating (toilets by house) Figure 27 groups all of the individual toilet flushes during February according to the WELS star rating. Sixty-two percent of all toilet flushes were greater than 5.5 L and hence had a 0 star rating. Figure 28 groups the average toilet flushes from the individual houses. Only one house achieved a 3 star WELS rating, whereas 74% achieved 0 stars. Retrofitting toilets in these homes to more efficient models would have an impact on overall water usage. A leak is defined as recorded water going into the property, but is not used by an appliance (e.g. dripping taps). Leaks represent 13% of the total water usage (on a household basis 24% on a per person basis) across all the study homes throughout the February period. The largest recorded leak was 89% of the total uses or 2,300 L/d. This was due to a broken pipe under the house, which has been fixed by the owner. This single home was responsible for 77% of the total leaks of the whole study group, hence the high percentage of leakage. As this was a single person household, the per person leakage rate is respectively higher. The five houses (11%) with the highest leakage rates were responsible for 98% of the total leakage. Eighty percent of houses had a leakage rate of 1% of the total water uses or lower Outdoor use and irrigation Outdoor use accounted for 16% of the total uses (on a household basis 13% on a per person basis). The largest outdoor use had a duration of 6 hours and used 6,362 L of water, which was due to irrigation as confirmed by the occupant Volume (L/day) % of total use Cumulative frequency (%) Houses Figure 29: Outdoor usage Figure 29 shows the distribution of outdoor uses throughout the study group based on the individual households. The largest outdoor use proportion of any house was 51% of total uses, or 800 L/d this made up 21% of all outdoor uses recorded in the whole study group. This particular upmarket house had a large swimming pool, spa pool and a sprinkler system in place (used for 1 hour most days). The swimming pool was topped up occasionally during this period. It is not possible to accurately identify and Page 35 of 118 Pages

36 distinguish between the individual outdoor uses (e.g. irrigation, pool/spa filling, car washing and others) with the methodology used. Hence these individual events are grouped into the outdoor use category. Eleven percent of the houses were responsible for nearly 5 of total outdoor uses during the February period Dishwasher Sixty-one percent of homes had a dishwasher installed. This appliance represented only 1.5% of the indoor uses (average of 2.5% for homes with a dishwasher). When comparing tap usage in homes with and without a dishwasher, no justifiable relationship was found. The initial expectation was that homes with a dishwasher would use less water for tap use (reduced washing of dishes in sink). 4.3 End use analysis March 2008 This section looks at the end use distribution during the March monitoring period. From the 51 house sample, data was lost from six houses ( 12%) during this period. Failure causes are discussed in the previous section. The individual end uses for March are discussed in section 4.4 where the end uses are directly compared to the data collected during February End uses per household (March 2008) The following graphs (Figure 30 to Figure 32) show the measured end uses for March 2008 on a household level. These are average values, as not every home has a dishwasher, washing machine or bathtub. Eighteen percent of the total household uses were outside uses, such as irrigation. The shower was the highest indoor use, followed by the washing machine and toilet. Leaks represented around 6% of the total usage. However this includes the home which had a major pipe leak during the start of the March monitoring period. These values have been adjusted in section OUTDOOR 18% Leaks 6. Tap 11.6% Bathtub 1.3% Misc 0.1% Shower 25.4% Dishwasher 1.3% Toilet 16.4% Washing machine 20.5% Page 36 of 118 Pages

37 Figure 30: Total end uses per household March period OUTDOOR 18.7% Misc 0.1% Bathtub 1.4% Tap 12.3% Dishwasher 1.4% Toilet 17.5% Shower 27. Washing machine 21.8% Figure 31: Total end uses per household (no leaks) March period Dishwasher 1.6% Toilet 21.5% Bathtub 1.7% Misc 0.1% Tap 15.1% Shower 33.2% Washing machine 26.8% Figure 32: Indoor end uses per household March period Page 37 of 118 Pages

38 The largest measured indoor event was the shower, accounting for 33% of all indoor uses, followed by the washing machine and the toilet with 27% and 22% respectively. Indoor taps (hot, cold and mixed) represented around 15% of indoor usage End uses per person The following graphs (Figure 33 to Figure 35) show the measured end uses for March 2008 on a per person basis. These are average values, and not every home has a dishwasher, washing machine or bathtub. The individual end uses will be discussed in the relevant sections. Leaks 10.7% Tap 11.6% OUTDOOR 15% Bathtub 1. Misc 0. Shower 23.7% Dishwasher 1.2% Toilet 16.7% Washing machine 20. Figure 33: Total end uses per person March period Page 38 of 118 Pages

39 Bathtub 1.1% OUTDOOR 16.9% Misc 0. Tap 12.9% Dishwasher 1.4% Toilet 18.7% Shower 26.6% Washing machine 22.4% Figure 34: Total end uses per person (no leaks) March period Dishwasher 1.7% Toilet 22.5% Bathtub 1.3% Misc 0.1% Tap 15.6% Shower 32. Washing machine 26.9% Figure 35: Indoor end uses per person March period Page 39 of 118 Pages

40 The largest measured indoor event during March was the shower, accounting for 32% of all indoor uses, followed by the washing machine and the toilet with 27% and 23% respectively. These values are comparable when looking at the measured February data and the summer monitoring data from WEEP, suggesting similar behaviour in indoor water usage and also that that indoor usage remains constant. This similarity, about constancy is also the expectation for the winter monitoring period End use adjustments As one of the homes had an unusual major leak, which went through one-and-a-half weeks of the March monitoring period, the end uses have been adjusted in this section by excluding this property. Figure 36 and Figure 37 show the adjusted results. On a household level the highest use was the shower, with 26% of the total uses, followed by the washing machine, outdoor uses and the toilet, with 21%, 18% and 17% respectively. Indoor taps were responsible for 12% of the total usage and leaks for 3%. Minor uses such as the bathtub and dishwasher made up just over 1% each of the total usage. OUTDOOR 18% Leaks 2.6% Tap 11.9% Bathtub 1.4% Dishwasher 1.4% Shower 26.4% Toilet 16.7% Washing machine 21.3% Figure 36: Household end use distribution (excluding major leakage home) When looking at the data on a per person basis, similar results can be observed (Figure 37). Page 40 of 118 Pages

41 OUTDOOR 17% Leaks 3.3% Tap 12.4% Bathtub 1.1% Dishwasher 1.3% Shower 25.9% Toilet 17.4% Washing machine 21.9% Figure 37: Per person end use distribution (excluding major leakage home) 4.4 End use analysis summer monitoring period This section compares the adjusted (excluding major leak) (Table 7) and indoor (Table 8) water end uses between February and March Table 7: Total end use comparison (adjusted values) Total uses per person Total uses per household End use Auckland February Auckland March WEEP Summer Auckland February Auckland March Tap 12% 12% 12% 11% 12% Shower 24% 26% 22% 25% 26% Washing machine 23% 22% 21% 22% 21% Toilet 18% 17% 17% 17% 17% Dishwasher 1% 1% 1% 1% 1% Bathtub 2% 1% 2% 2% 1% Misc 1% Outdoor 17% 17% 22% 18% 18% Leaks 4% 3% 3% 3% 3% TOTAL The measured data for Auckland shows similar results throughout February and March, with nearly identical usage patterns, as far as the total and indoor end use distributions are concerned. Even when comparing the figures with WEEP, the distributions are Page 41 of 118 Pages

42 Relative frequency (%) nearly identical. The main difference is a higher outdoor use proportion on the Kapiti Coast than in Auckland. Table 8: Indoor end use comparison Indoor uses per person Indoor uses per household End use Auckland February Auckland March WEEP Summer Auckland February Auckland March Tap 15% 16% 16% 15% 15% Shower 31% 32% 3 32% 33% Washing machine 28% 27% 27% 27% 27% Toilet 23% 23% 23% 22% 22% Dishwasher 2% 2% 2% 2% 2% Bathtub 2% 1% 2% 2% 2% Misc 1% 1% TOTAL Shower With around 26% of the total uses, the shower was the highest water usage during the summer. The average duration was around 6.6 min during the whole period, with a median of 5.5 min and a standard deviation of 4.3 min. In total 5,709 showers had been observed from all of the homes during the two months of monitoring. Figure 38 shows a graphical comparison between the two separate months, as well as a distribution over the whole period. 16% 14% 12% 1 February March All Average Median Stdev Count 3,192 2,517 5,709 8% 6% 4% February March All 2% Minutes Figure 38: Shower duration summer monitoring period Page 42 of 118 Pages

43 Relative frequency Relative frequency On average around 50 L are used for each shower, with a median of 40 L and standard deviation of 39 L. Figure 39 shows the distribution of volumes and graphical comparison of the summer monitoring period. 2 18% 16% 14% 12% February March All Average Median Stdev Count 3,192 2,517 5, % 6% 4% 2% February March All Litres Figure 39: Shower volumes summer monitoring period 14% 12% 1 8% February March All Average Median Stdev Count 3,192 2,517 5,709 6% 4% 2% February March All Litres per minute Figure 40: Shower flow rates summer monitoring period Page 43 of 118 Pages

44 Relative frequency The average shower flow rate for the summer period was around 8 Lpm, with a median of 7.5 and a standard deviation of 3.4. This is comparable to a 3 star WELS rating. The reason why the number of showers below 3 Lpm are lower in March is that data was lost from the eight person household, which was responsible for the majority of showers at this low flow rate, since their shower was only capable of producing this low rate. When looking at the WELS rating (Figure 41) of all the monitored shower events (over 5,700), 49% of events are above a 3 star (maximum efficient) rating. Sixteen percent would receive 3 stars, 22% 2 stars, 12% 1 star, and just under 2% would receive 0 stars. This shows that most systems are already very efficient when using the WELS scale. Adopting WELS for the study homes, limited water savings would be achieved. A review of the shower flow bands for the star rating might need to be considered. This will be explored further in the final report. 6 Less than 7.5 Lpm than 7.5 not more than 9 than 9 not more than 12 than 12 not more than 16 than 16 Lpm % % 16.1% 11.5% 1.6% above 3 Stars 3 Stars 2 Stars 1 Star 0 Stars WELS rating Figure 41: Shower flow efficiencies according to WELS When examining the type of domestic hot water (DHW) system, which was mainly electric cylinders (77%) or gas (18%) (two systems included solar water, boosted by electric; three were unknown), variation in shower flow rates can be seen (Figure 42). A similar fuel distribution for DHW systems has been found in HEEP (Isaacs 2006). Electric cylinder systems generally had lower shower flow rates (7.8 Lpm average) when compared to gas systems (10.3 Lpm). This suggests that a shift from electric systems to gas systems would result in a higher shower flow rate, which would result in a higher water use in the shower. Just over 5 of electric systems would receive a 3 star WELS rating for the shower system as compared to just over 11% of the gas systems. Note that these are average values, and only nine gas systems were represented in the study. Page 44 of 118 Pages

45 Relative frequency Relative frequency (in Lpm) Electric Gas Average Stdev min max Count Electric Gas above 3 Stars 3 Stars 2 Stars 1 Star 0 Stars WELS RATING Figure 42: Shower flows according to hot water system On average 0.9 showers are taken per person per day during the summer monitoring period. Figure 43 shows the distribution. Shower usage during February and March is very similar, as suggested by the measured data, strengthening the hypothesis that indoor usage remains constant. Shower flow rate, duration and hence volumes used have slightly increased from February to March. But the overall daily volumes have decreased, due to a slight decrease in shower frequency. 4 35% 3 25% February March ALL Average Median Stdev % 1 5% February March All > 1.6 Showers/person/day Figure 43: Average number of showers per person per day Page 45 of 118 Pages

46 below Above 190 Relative frequency Washing machine The washing machine is the second highest indoor use, representing around 27% of the indoor uses. During the two summer months 1,954 loads of washing have been undertaken. 3 25% 2 15% 1 5% February March ALL Average Median Stdev Count February March All Litres/load Figure 44: Average washing machine volumes per load As only three machines were front-loading, it is not statistically relevant to distinguish between the two types of systems, even though front-loading machines generally use less water than top-loading. Ninety-four percent of machines in the study group were top-loading. Figure 44 shows the distribution of average washing machine load volumes for each of the houses. On average a load of washing used 122 L per load. The highest volume for any load was 190 L and the lowest 51 L Number of loads On average 5.6 loads per week (0.8 loads per day; 0.35 loads per person per day) of washing were undertaken per home. There is a strong correlation between the average number of loads of washing and the household size. This relationship is shown in Figure 45 and Figure 46. For a household size of four and above, the sample size is comparatively small and the eight person household did not have a washing machine. In Figure 46 the average number of loads of all the houses have been plotted. This shows clearly the range of the number of loads within each of the household size groups. When looking purely at two person households, the minimum number of loads per week is around 1.8 and the maximum is 10. The derived formulae might not be accurate to calculate the number of loads for an individual household, but can be used for calculating this figure for a larger group. For a household size of four and above, the number of individual homes within each group (n-value) gets too small to make generalisations. Page 46 of 118 Pages

47 Loads/week Number loads week HH size n Feb March ALL Average loads per week y = 2.17x R 2 = Feb 4 2 March ALL Linear (ALL) Household size Figure 45: Relationship between household size and average number of loads y = 1.80x R 2 = Household size February March ALL Linear (ALL) Linear (March) Linear (February) Figure 46: Relationship between household size and average number of loads (plotting each house individually) Page 47 of 118 Pages

48 Relative frequency Relative frequency Indoor taps Indoor tap use represents around 12% of total water usage (15% of indoor usage). During the summer monitoring period, a total of over 143,000 individual events have been recorded from the study homes February March All Average Median Stdev Count 77,971 65, ,084 February March All 1 Seconds Figure 47: Indoor tap use duration summer monitoring period 45% 4 35% 3 25% 2 15% 1 5% February March All Average Median Stdev Count 77,971 65, ,084 February March All Litres Figure 48: Indoor tap use volumes summer monitoring period The average use duration was around 25 seconds, with a median of 20 and a standard deviation of 34 seconds (Figure 47). As we have used a 10 second monitoring interval, a further breakdown in data would require a shorter logging interval (e.g. 5 seconds). Even if a tap was used for 1 second, the duration would be recorded as 10 seconds or a use of 11 seconds would be recorded as 20 seconds (10 second increments). Hence, Page 48 of 118 Pages

49 Relative frequency the values for tap use duration are only accurate to ±10 seconds. However, the usefulness of these results is that it can be seen that most tap events have a relatively short duration. Long durations which last several minutes are rare e.g. leaving the tap running while brushing teeth or shaving. The volume distribution in Figure 48 shows the amount of water used in each of the individual tap use events. On average 0.9 L of water were used for a single tap event, with a median of 0.4 L and a standard deviation of 1.4 L. Thirty-seven percent of events use 0.25 L of water or less and 9 use 2.25 L or less. Tap use is a low volume, but high frequency, event as each person uses the tap around 24 times each day, more than any other water-using appliance. The average tap flow rate was measured to be 2.6 Lpm, with a median of 1.8 Lpm and a standard deviation of 2.5 Lpm (Figure 49). When plotting all 140,000 individual tap events on a WELS scale (Figure 50), it can be seen that 82% of events would receive a maximum efficient rating of 6 stars. Only less than 1% of events would receive 1 or 0 stars. From a demand management point of view, reducing the flow of taps would not be as feasible, as most taps are already being used at maximum efficient flows, even if they are capable of higher flows. Table 9 shows a summary of tap usage. Table 9: Tap use summary February March All Average no. tap uses/person Average duration (sec) Average volume/use (L) Average flow rate (Lpm) % 3 25% 2 15% February March All Average Median Stdev Count 77,971 65, , % February March All Litres per minute Figure 49: Indoor tap use flow rates summer monitoring period Page 49 of 118 Pages

50 < Relative frequency Relative frequency Less than 4.5 Lpm than 4.5 not more than 6 than 6 not more than 7.5 than 7.5 not more than 9 than 9 not more than 12 than 12 not more than 16 than 16 Lpm % % 4.2% 2.9% 2.2% 0.6% 0.1% star 5 star 4 star 3 star 2 star 1 star No star WELS rating Toilet Figure 50: Individual tap flows ranked according to WELS Over the two month summer monitoring period, a total of 28,701 individual toilet flushes have been recorded. The toilet represents around 23% of the indoor uses. Figure 51 shows the distribution of toilet flush volumes. The average flush volume (half and full flush were not distinguished) was around 6.6 L per flush, with a median of 6.6 L and a standard deviation of 2.7 L. 12% 1 8% February March All Average L Median L Stdev L Count 16,069 12,632 28,701 6% 4% 2% February March All Litres Figure 51: Toilet flush volume distribution summer monitoring period Page 50 of 118 Pages

51 > 15 Relative frequency On average each person would flush the toilet in their home five times per day. This rate is constant throughout the summer as the distribution in Figure 52 suggests. The same figure of toilet flush frequency has been found in WEEP. 18% 16% 14% 12% 1 8% 6% 4% 2% February March All Average Median Stdev February March All Flushes Figure 52: Average toilet flushes per person per day Not more than 2.5 L than 2.5 not more than 3 than 3 not more than 3.5 than 3.5 not more than 4 than 4 not more than 4.5 than 4.5 not more than 5.5 than 5.5 L % % February 19.6% March 2.2% 2.2% 4.3% 2.2% 2.2% 6 stars 5 stars 4 stars 3 stars 2 stars 1 stars 0 stars Figure 53: WELS star rating (toilets by house) If plotting the average flush volumes for each home on a WELS scale (Figure 53), it can be seen that the large majority of flush volumes per home have a very low Page 51 of 118 Pages

52 % of total leakage Leaks efficiency rating (mainly 0 stars). The reason why a higher percentage of average flush volumes received a 1 star rating during the February period is that many of these flushes were at the border towards the lower side of the rating scale (e.g. 5.4 L) and hence the categorical shift. The adaptation of WELS for reducing water use by toilet retrofit would have an impact on overall water use, especially replacing larger cistern single flush toilets (e.g. 12 L /flush) with more efficient models (e.g. 6 star model). Leaks made up 13% of the total water usage (on a household basis 24% on a per person basis) across all the study homes through the February period. During March this share dropped to 6% of total household use (11% of per person use). This drop was mainly due to a large leak being fixed in one of the houses during March. This particular leak was 89% of this home s total use (or 2,301 L/day during February) and dropped to 71% of total uses (or 654 L/day in March). This single leak was responsible for the majority of leaks during the summer period. During February this particular leak represented 77% of all leaks combined. During February, nearly 8 of the homes had leaks, which accounted for less than 1% of their total use, averaging just over 1 L per day. During March this group was reduced to 71%. For the majority of houses the leakage rate remains fairly similar across the two periods. Two other homes have reduced their leakage rate substantially, whereas other homes introduced new leaks. If the major leak (broken water pipe) of this one particular home is disregarded, the overall leakage rate during February and March remained fairly constant, with leaks making up around 3% of the total household uses (around 3 4% of total per person usage). These values for the adjusted summer leaks are identical with data collected in WEEP to one decimal point exactly (3.3%). Figure 54 shows a cumulative frequency graph of the leaks from each of the houses February March February March Highest % leaks 89% 71% Highest L/day Houses Figure 54: Share of total leakage Page 52 of 118 Pages

53 4.4.6 Outdoor Outdoor usage represented around 18% of the total household usage (17% of per person usage) during both the February and March period. The house with the highest usage during February was also the highest outdoor user during March. The term outdoor use can include many different individual uses. It includes: irrigation, which is the main outdoor use; the filling and topping up of swimming pools and spa pools; car washing; footpath cleaning; recreation; and other uses. The two houses which had outside swimming pools also had very high outdoor water usage during the whole summer period. One of these houses also had an automatic sprinkler system, which was used for 1 hour nearly every day, using 900 L during this period. The largest single use outdoor event during February had a duration of 6 hours, using a total of 6,362 L during this period. During March the highest single use was another 6 hour event using just under 5,000 L. Figure 55 shows the average daily Figure 55: Outdoor water usage volumes of outside uses of the study homes across the two summer monitoring periods (only households with outdoor uses are shown in the graph). Even though the overall outdoor usage was uniform over the whole summer period, houses that had a high outdoor usage during February did not necessarily have a high outdoor usage during March and vice versa Houses February Litres/day March Daily profiles summer period Figure 56 shows the daily profiles of the summer monitoring period. A sharp rise in water flows can be observed at around 6:30 in the morning and at around 17:00 in the evening. These are the main times when people are at home. The peak between 21:00 and 22:00 is mainly due to the operation of an automatic sprinkler system in one of the properties, which was used nearly daily at the same time. Also the night peak at around 3:00 is due to another automatic sprinkler system, which was mainly used during February, due to the dry conditions. The maximum average flow was about 50 L per hour (Lph) during February and 40 Lph during March. The daily profile for February is in close correlation to the March profile, which again suggests similar usage behaviour between the two monthly periods. The variation in flow profiles of weekend and weekdays is shown in Figure 57. On the weekend (Saturday and Sunday) the morning peak occurs at around 9:00 to 10:00, whereas during the week the morning peak occurs at around 7:00 and 8:00. During these morning periods the highest flows can be observed, which are around 50 Lph Page 53 of 118 Pages

54 Average Litres/hour Average Litres/hour during the weekend and 52 Lph on weekdays. Troughs in flow occur at around 23:00 until 5:00, where the flow rate is below 10 Lph. At around 14:00 to 17:00 during the weekend the flow is below 25 Lph. During weekdays this afternoon low flow period occurs from around 10:00 to 17:00, with the flow rate being below 20 Lph February March ALL :00 02:00 04:00 06:00 08:00 10:00 12:00 14:00 16:00 18:00 20:00 22:00 Figure 56: Average daily flow profile (10 min time steps) Weekday Weekend :00 2:00 4:00 6:00 8:00 10:00 12:00 14:00 16:00 18:00 20:00 22:00 Figure 57: Average weekday/weekend profiles (10 min time steps) Page 54 of 118 Pages

55 The evening peaks during both periods roughly follow the same pattern. From 22:00 a rapid decrease in water use can be observed. During the weekend higher water flows occur during the daytime period than the weekdays. The average hourly flow during the weekend is around 22 Lph and during weekdays around 18 Lph (average of 20 Lph over whole week). 5. WINTER MONITORING PERIOD The winter period is defined as June/July and up to 5 weeks of data from each of the homes has been analysed for this period. From the 51 house sample, data was lost from three houses ( 6%) during this period, which is lower than during the summer. 5.1 End use analysis winter 2008 The focus of this section is to look at the monitored end uses in detail. Information and details on the volumetric water usage during this period can be found in section 6.1, which is a comparison between winter and summer water usage End uses per household The following graphs (Figure 58 to Figure 60) show the measured end uses for February 2008 on a household level. These are average values, as not every home has a dishwasher, washing machine or bathtub. Misc 0.4% Bathtub 1.7% OUTDOOR 6% Leaks 2.2% Tap 15.6% Dishwasher 1.3% Toilet 17.5% Washing machine 22.7% Shower 32.8% Figure 58: Total end uses per household winter period Page 55 of 118 Pages

56 Misc 0.4% Bathtub Dishwasher 1.8% 1.4% OUTDOOR 5.9% Tap 15.9% Toilet 17.9% Washing machine 23.2% Shower 33.5% Figure 59: Total end uses per household (no leaks) winter period Dishwasher 1.6% Bathtub 1.9% Misc 0.4% Toilet 19. Tap 16.9% Washing machine 24.7% Shower 35.6% Figure 60: Indoor end uses per household winter period Page 56 of 118 Pages

57 The largest measured indoor event was the shower, accounting for 36% of all indoor uses, followed by the washing machine and toilet with 25% and 19% respectively End uses per person The following graphs (Figure 61 to Figure 63) show the measured end uses for June/July 2008 on a per person basis. These are average values, as not every home has a dishwasher, washing machine or bathtub. The individual end uses will be discussed in the relevant sections. Misc 0.5% Bathtub 1.2% Dishwasher 1.3% OUTDOOR 6% Leaks 2. Tap 16.3% Toilet 18.5% Washing machine 24.3% Shower 29.6% Figure 61: Total end uses per person winter period Page 57 of 118 Pages

58 Bathtub 1.3% Dishwasher 1.3% Toilet 18.9% Misc 0.5% OUTDOOR 6.4% Tap 16.7% Washing machine 24.8% Shower 30.2% Figure 62: Total end uses per person (no leaks) winter period Dishwasher 1.4% Toilet 20.2% Bathtub 1.4% Misc 0.5% Tap 17.8% Washing machine 26.5% Shower 32.3% Figure 63: Indoor end uses per person winter period Page 58 of 118 Pages

59 The largest measured indoor event was the shower, accounting for 32% of all indoor uses, followed by the washing machine and the toilet with 27% and 2 respectively. These values are comparable when looking at the winter monitoring data from WEEP (Table 10), suggesting similar behaviour in indoor water usage. Table 10: Comparison of winter indoor uses Auckland WEEP Tap 17.8% 15. Shower 32.3% 30.5% Washing machine 26.5% 27. Toilet 20.2% 21. Dishwasher 1.4% 1. Bathtub 1.4% 4. Misc 0.5% Volumetric end uses TOTAL Table 11 shows a summary of end uses and the average volumes used per home and per person. The daily indoor demand during winter for Auckland was 161 L/p/d (391 L/d), which is comparable to volumes measured in WEEP (147 L/p/d). When looking at the individual volumes for each of the end uses, similarities can be seen between both studies. Slightly lower volumes were used in the WEEP homes for the three main end uses (shower, toilet and washing machine) as compared to the Auckland homes, whereas outdoor uses were slightly higher in WEEP. Table 11: Average volume per end use during winter period Auckland (winter) WEEP (winter) per household per person per person INDOOR % l/d % l/p/d % l/p/d Tap Shower Washing machine Toilet Dishwasher Bathtub Misc TOTAL INDOOR Outdoor Leaks TOTAL USE 100.2* * * *not 10 due to rounding The winter volume distributions are discussed in section 6.1 and a deeper comparison between the Auckland study and WEEP can be found in section 7. Page 59 of 118 Pages

60 Relative frequency Relative frequency Shower The shower was found to be the highest water use, accounting for 32% of indoor uses (on a per person basis) during the June/July monitoring period. 14% 10 12% 1 Average = 7.0 minutes Median = 6.2 minutes Std deviation = 4.1 minutes % 6 5 6% 4 4% 3 2% 2 1 Minutes Figure 64: Shower duration 14% 10 12% % Average = 52.7 L Median = 42.4 L Std deviation = 38.6 L % 4 4% 3 2% 2 1 Minutes Figure 65: Shower volume distribution Page 60 of 118 Pages

61 Relative frequency A total of 3,136 shower events were recorded for the study group within this period. The average shower time was 7 min at an average flow rate of 8.0 Lpm. The average volume for each shower event was 52.7 L. On average each person in the study group had 0.9 showers per day (2.5 showers per house per day). From the graph in Figure 64 it can be seen that 8 of the showers have a duration of 2 10 min. Only 14% are longer than 11 min and only 5% are 2 min or less. The median was 6.2 min, with the average being 7 min, and a standard deviation of 4.1 min. Figure 65 shows the distribution of shower volumes. Ninety percent of the showers used 100 L of water or less per event. The median was 42.4 L, the average volume was 52.7 L, and the standard deviation was calculated to be 38.6 L. The largest volume used by a single shower event was 319 L. The shower flow rates have a median of 7 Lpm, an average of 8 Lpm, and a standard deviation of 3.7 Lpm. The lowest average flow rate was found to be 3.4 Lpm and the maximum average flow for any shower event was 27.4 Lpm. The distribution in Figure 66 shows that 83% of shower events had a flow rate of between 4 and 12 Lpm. Only 2% of showers had a flow rate of more than 16 Lpm, which specifies a 0 star rating under the proposed WELS for New Zealand (Figure 19). The maximum star rating for showers under WELS (MCA 2007) is currently 3 stars. Due to the large proportion of 3 star rated shower flows in this study, a re-examination of the flow bands might need to be considered to achieve the anticipated results. If less than only 2% of shower flows do not obtain a star rating, there will be no incentive for improving efficiencies. 18% 16% 14% 12% 1 8% 6% 4% 2% Average = 8.0 Lpm Median = 7.0 Lpm Std deviation = 3.7 Lpm Litres per minute Figure 66: Shower flow rates Page 61 of 118 Pages

62 Relative frequency Less than 7.5 Lpm than 7.5 not more than 9 than 9 not more than 12 than 12 not more than 16 than 16 Lpm 6 55% % 14% 11% 2% above 3 Stars 3 Stars 2 Stars 1 Star 0 Stars WELS star rating Figure 67: WELS star rating Washing machines The washing machine accounts for 27% of indoor uses (on a per person basis). The average load for the study group was measured to be 123 L, with an average of 0.8 loads being washed per house per day (0.4 loads per person per day). Table 12 summarises this data. Figure 68 shows the distribution of average washing machine volumes across the study homes. Only 2 of washing machines in the study group use an average of 100 L or less per load. Fifteen percent use more than 150 L per load. Table 12: Summary of washing machine use Average Standard deviation Litres/load Loads/house/day Loads/person/day Litres/house/day Litres/person/day Page 62 of 118 Pages

63 below Above 190 Relative frequency 25% % % 2 1 Litres/load Figure 68: Washing machine average load volumes Indoor taps Indoor tap use (hot, cold and mixed) accounts for 18% of indoor uses. A total of 70,633 individual tap uses were registered during the June/July monitoring period. A tap use event has a distinctive start and finish. If both hot and cold water taps are used simultaneously, it is still defined as one event. On average, taps would be used 23 times per person per day. The distribution in Figure 69 shows that 69% of tap uses are 20 seconds or less. Since the data was collected at a 10 second interval, a further breakdown in data would require a shorter logging interval (e.g. 5 seconds). The average tap use time is 26 seconds, with a median of 20 seconds, and a standard deviation of 30 seconds. The distribution in Figure 70 shows the total volumes used in each tap event. Sixty-nine percent of tap use events use 1 L or less and only 9% use more than 3 L. The average volume of each event is 1.1 L, the median 0.5 L, and the standard deviation 1.8 L. The distribution of tap flow rates is shown in Figure 71. Seventy-nine percent of tap usage has a flow of less than 4.5 Lpm (6 star WELS rating). The average flow rate of a tap event is 2.9 Lpm, the median 2.1 Lpm and the standard deviation 2.7 Lpm. Page 63 of 118 Pages

64 Relative frequency Relative frequency 45% 4 35% 3 25% 2 15% 1 5% Average = 26 seconds Median = 20 seconds Std deviation = 30 seconds Seconds Figure 69: Tap use duration 35% 3 25% % 1 5% Average = 1.1 L Median = 0.5 L Std deviation = 1.8 L Litres Figure 70: Tap use volumes Page 64 of 118 Pages

65 Relative frequency Relative frequency % % Average = 2.9 Lpm Median = 2.1 Lpm Std deviation = 2.7 Lpm 4 3 5% 2 1 Litres per minute Figure 71: Tap flow rate distribution 10 Less than 4.5 Lpm than 4.5 not more than 6 than 6 not more than 7.5 than 7.5 not more than 9 than 9 not more than 12 than 12 not more than 16 than 16 Lpm 9 88% % 3% 3% 1% 6 star 5 star 4 star 3 star 2 star 1 star No star WELS star rating Figure 72: WELS star rating (taps in litres per minute) Page 65 of 118 Pages

66 Relative frequency Toilet Figure 72 shows the measured tap flow rates and ranks them according to the proposed WELS star rating, which shows that the majority of tap uses have a high star rating. Even if the taps might be capable of higher flow rates, this does not necessarily mean that taps get used at these maximum flows. One reason for this could be due to restrictions of the basin, which might only handle lower flows. For example, higher tap flows can cause the water to spray onto the floor or surroundings, due to higher impact energies. This is an important finding, as reducing the flow rates of taps might not yield the desired results. To confirm this finding, future questionnaire data needs to include questions on individual tap use behaviour. The toilet accounted for 2 of indoor uses (on a per person basis). A total of 13,589 individual toilet flushes were recorded from all the homes during the June/July monitoring period. On average 4.6 flushes per person per day were recorded (Figure 73). The average flush volume across the study homes was 6.8 L, the median 6.8 L and the standard deviation 2.4 L. A number of homes still have 12 L single flush toilets or larger (Figure 74). However toilets can be responsible for a large proportion of leaks, hence major savings can be achieved by fixing these (e.g. changing seals). This is confirmed by the flow trace analysis methodology, as leaks can be seen visually. If a toilet valve does not shut off properly, then the flow profile continues. An example of this is included in Appendix B. 25% % Average = 4.6 Flushes Median = 3.8 Flushes Std deviation = 3.3 Flushes % 2 1 Number of flushes / person /day Figure 73: Average toilet flushes per person per day Page 66 of 118 Pages

67 Relative frequency Relative frequency 12% 1 8% 6% 4% 2% Average = 6.8 L Median = 6.8 L Std deviation = 2.4 L Litres Figure 74: Toilet flush volumes In the analysis it was not distinguished between half and full flush, but when plotting all the toilet events, 69% of flushes were above 5.5 L (0 stars). Overall 80 toilets were installed in the 51 homes, of which 28% were single flush. Ninety-one percent of all toilets would receive a 0 star rating under WELS. Thirty percent of homes still had at least one single flush toilet, which used up to 12 L per flush. Not more than 2.5 L than 2.5 not more than 3 than 3 not more than 3.5 than 3.5 not more than 4 than 4 not more than 4.5 than 4.5 not more than 5.5 than 5.5 L % % 1% 2% 2% 6% 6 stars 5 stars 4 stars 3 stars 2 stars 1 stars 0 stars WELS Star Rating Figure 75: WELS star rating (toilets all individual flushes) Page 67 of 118 Pages

68 Relative frequency Not more than 2.5 L than 2.5 not more than 3 than 3 not more than 3.5 than 3.5 not more than 4 2% 7% 91% 6 stars 5 stars 4 stars 3 stars 2 stars 1 stars 0 stars WELS Star Rating than 4 not more than 4.5 than 4.5 not more than 5.5 than 5.5 L Leaks Figure 76: WELS star rating (toilets by house) Figure 75 groups all of the individual toilet flushes during June/July according to the WELS star rating. Sixty-nine percent of all toilet flushes were greater than 5.5 L and hence had a 0 star rating. Figure 76 groups the average toilet flushes from the individual houses. Only one house achieved a 2 star WELS rating, whereas 91% achieved 0 stars. Retrofitting toilets in these homes to more efficient models would have an impact on overall water usage. Leaks represent only 2% of the total water usage across all the study homes throughout the June/July period. This was a substantial reduction to the summer monitoring months. However during the two monitoring periods, some homes showed unusually high usage behaviour. After looking at some of the files in detail, it became apparent that these houses had continuous leaks Outdoor use and irrigation Outdoor use accounted for 6% of the total uses. The largest outdoor use had a duration of just under 3 hours and used 2,932 L of water. Generally during the winter, outdoor events had much lower volumes than during the summer. Outdoor events include uses such as filling pools and spa pools, garden irrigation (main events) and others. The house with the highest outdoor use during the winter period was also responsible for the highest use during the summer Dishwasher Sixty-one percent of homes had a dishwasher installed. This appliance represented only 1.4% of the indoor uses. As this use is minimal, it is not discussed in further detail. Page 68 of 118 Pages

69 Relative frequency Cumulative frequency 6. SUMMER / WINTER MONITORING PERIOD COMPARISON The main focus of this chapter is to see the seasonal variations in residential water usage. This is achieved by directly comparing the data obtained during summer (average of February and March) and during winter (June/July data). The data from the February and March period is referred to as summer usage and the June/July data is referred to as winter usage. 6.1 Volume usage comparison summer and winter period This section compares the daily volumes and daily peak volumes during the winter and summer monitoring periods Total daily use The average daily use per household during June/July 2008 was 425 L, with an average of 2.7 people living in each home (Figure 77). Over the summer the daily household usage was 422 L, which is 3 L lower than the winter usage. This slightly higher figure may be due to the fact that more people were at home during the winter than during summer (i.e. less days with 0 L usage), which increased the average daily volumes). The median values are also lower during the winter than during summer (319 L/d as compared to 328 L/d). Eighty percent of daily uses during the summer were between 80 and 680 L as compared to 78% during winter. Five percent of daily uses during both the summer and winter were 1,000 L and more. The two curves on the graph that represent the cumulative frequency are almost identical, suggesting similar usage patterns over both monitoring periods. 9% 10 8% 9 7% 6% 5% 4% 3% 2% 1% SUMMER WINTER Average (L/d) Median (L/d) StDev (L/d) Max (L/d) SUMMER WINTER SUMMER WINTER Litres / day Figure 77: Distribution of litres per household per day Page 69 of 118 Pages

70 Relative frequency Cumulative frequency Daily per capita use The average daily per capita use for the summer was found to be 179 L and 175 L during the winter. The distribution in Figure 78 shows that 8 of the daily water uses during the summer are 240 L/p/d or less, compared to 84% during the winter. Eleven percent of daily water uses per person during the summer are above 300 L as compared to 9% over the winter. The highest daily usage during summer was 3,481 L per person, whereas during winter the highest usage was measured to be 1,937 L. 14% 12% 1 8% 6% 4% 2% SUMMER WINTER Average (L/p/d) Median (L/p/d) StDev (L/p/d) Max (L/p/d) SUMMER WINTER SUMMER WINTER Litres / person / day Figure 78: Distribution of litres per person per day Peak daily demand Figure 79 shows the peak water demand from each of the households. The peak daily demand was 1,649 L/d (median 938 L/d) over the whole summer monitoring period (not average values of February and March, but maximum daily values over the whole period). During winter the peak daily demand was 1,102 L/d (median 756 L/d), which is 547 L less than the summer peak. The standard deviation for the winter period is also lower, which suggests that the range of peak daily uses is also lower during the winter. The highest single day use across the whole study group was 7,200 L/d, which was mainly due to outside water usage. Seventy-nine percent of daily peak uses during the summer were below 2,000 L/d, as compared to 89% during the winter. The per person peak demand is shown in Figure 80, averaging at 683 L/p/d over the summer period (median 427 L/p/d), as compared to 468 L/p/d during winter (median 327 L/p/d). Page 70 of 118 Pages

71 Relative frequency Relative frequency The highest daily use during the summer period was 3,480 L/p/d, which was recorded during February. During the winter period the highest daily per person use was only 1,937 L/p/d, which is still higher than peak volumes measured during March. Seventyfour percent of daily peak uses for the summer were below 800 L/p/d as compared to 86% during the winter. (Seventy-nine percent of February peak uses and 85% of March uses were below 800 L/p/d.) 7 6 SUMMER WINTER Average (L/d) Median (L/d) StDev (L/d) Max (L/d) SUMMER WINTER 1 < Litres / day Figure 79: Daily household peak demand 35% 3 25% 2 15% SUMMER WINTER Average (L/p/d) Median (L/p/d) StDev (L/p/d) Max (L/p/d) SUMMER WINTER 5% < Litres / person / day Figure 80: Daily per person peak demand Page 71 of 118 Pages

72 6.2 End use analysis summer and winter comparison This section compares the total and indoor water end uses between the summer (February and March 2008) and winter (June/July 2008) monitoring periods. Table 13 shows a summary of the measured end use proportions. During the summer, there was a much higher proportion of outdoor uses and leaks than during winter. When comparing solely between the indoor uses it can be seen that indoor use proportions remained fairly constant over both monitoring periods. There was a slightly higher tap use proportion and lower toilet use proportion during the winter period. During the winter, 92% of total water use was indoors (94% if including leaks). Table 13: Winter end use comparison (per person) ALL USES INDOOR USES End use Summer Winter Summer Winter Tap 12% 16% 15% 18% Shower 25% 3 31% 32% Washing machine 23% 24% 27% 27% Toilet 18% 19% 23% 2 Dishwasher 1% 1% 2% 1% Bathtub 2% 1% 1% 1% Misc 1% 1% TOTAL INDOOR 8 92% Outdoor 17% 6% Leaks 4% 2% TOTAL The following sub-sections look at these variations in more detail, as each of the end uses are explored individually and compared over the summer and winter period Shower With around 25% of the total uses during summer and 3 during winter, the shower was the highest water usage during both periods. The average shower duration during summer was around 6.6 min, with a median of 5.5 min and a standard deviation of 4.3 min. During winter, there was a slight increase in shower duration, which averaged at 7 min (median of 6.2 and standard deviation of 4.1). In total 8,842 shower events have been observed from all of the homes during both monitoring periods. Figure 81 shows a graphical comparison between the two separate monitoring periods. Page 72 of 118 Pages

73 Relative frequency Relative frequency 16% 14% 12% 1 8% 6% 4% 2% SUMMER WINTER Average Median Stdev Count (n) 5,709 3,136 SUMMER WINTER Minutes Figure 81: Shower duration summer / winter comparison On average around 50 L are used for each shower during the summer, with a median of 40 L and standard deviation of 39 L. During the winter this value increased slightly to 53 L (median of 42 L and standard deviation of 38 L). Figure 82 shows the distribution of volumes and graphical comparison of the summer monitoring period. 2 18% 16% 14% 12% 1 8% 6% 4% 2% SUMMER WINTER Average Median Stdev Count (n) 5,709 3,136 SUMMER WINTER Litres Figure 82: Shower volumes summer / winter comparison Page 73 of 118 Pages

74 Relative frequency Relative frequency 18% 16% 14% 12% 1 8% SUMMER WINTER Average Median Stdev Count (n) 5,709 3,136 6% 4% 2% SUMMER WINTER Litres per minute Figure 83: Shower flow rates summer / winter comparison 6 Less than 7.5 Lpm 55% than 7.5 not more than 9 than 9 not more than 12 than 12 not more than 16 than 16 Lpm 5 49% SUMMER 22% WINTER 16% 18% 14% 11% 11% 2% 2% above 3 Stars 3 Stars 2 Stars 1 Star 0 Stars WELS star rating Figure 84: Shower flow rates according to WELS Page 74 of 118 Pages

75 Relative frequency The average shower flow rate (Figure 83) for both the summer and winter period was around 8 Lpm. This is comparable to a 3 star WELS rating. When looking at the WELS rating (Figure 84) of all the monitored shower events (over 8,800), 49% of events are above a 3 star (maximum efficiency) rating during the summer and 55% during the winter. Sixteen percent would receive 3 stars, 22% 2 stars, 12% 1 star, and just under 2% would receive 0 stars. This shows that most systems are already very efficient when using the WELS scale. By installing low flow shower heads (WELS rated) in the study homes, limited water savings would be achieved. A review of the shower flow bands for the star rating might need to be considered. Only one house had a header tank (low pressure system), but 77% of houses had electric DHW cylinders (Figure 42), which tend to be low pressure systems. Gas systems (18% of houses) supplied slightly higher shower flow rates (higher pressure). This is further discussed in section 0 On average 0.9 showers are taken per person per day during both the summer and winter monitoring period. Figure 85 shows the distribution. Shower usage during summer and winter is very similar, as suggested by the measured data, strengthening the hypothesis that indoor usage remains constant. Shower length, and hence shower volumes, have slightly increased from summer to winter. 35% 3 25% SUMMER WINTER Average Median Stdev % 1 SUMMER WINTER 5% > 1.6 Showers/person/day Figure 85: Average number of showers per person per day Page 75 of 118 Pages

76 below Above 190 Relative frequency Washing machine The washing machine is the second highest indoor use, representing around 27% of the indoor uses during both summer and winter. Overall 2,910 unique washing machine events have been observed over the two separate monitoring periods. 25% 2 15% SUMMER WINTER Average Median Stdev Count SUMMER WINTER 5% Litres/Load Figure 86: Average washing machine volumes per load As only three machines were top-loading, it is not statistically relevant to distinguish between the two types of systems, even though front-loading machines generally use less water than top-loading. Ninety-four percent of machines in the study group were top-loading, which corresponds to data collected in the HEEP study (Pollard 2007). Figure 87 shows the distribution of average washing machine load volumes for each of the houses. On average a load of washing used 122 L per load during the summer and 123 L per load over winter. The highest volume for any load was 190 L in the summer and 196 L during winter. The lowest average load size was 51 L and 67 L during summer and winter respectively Number of loads On average 5.6 loads per week (0.8 loads per day; 0.35 loads per person per day) of washing were undertaken per home during both the summer and winter periods. These measurements only take into account the households that use a washing machine. Overall washing machine use stayed fairly constant over the whole two periods, when considering the whole sample. There is a strong correlation between the number of loads of washing and the household size. This relationship is shown in Figure 87 and Figure 88. For a household size of four and above, the sample size is comparatively small, and the eight person household did not have a washing machine -, hence the graphs have a maximum of four people per household.. Page 76 of 118 Pages

77 Average number of loads per week Average number of loads per week HH size n SUMMER WINTER AVERAGE y = 1.63x R² = 0.98 y = 1.24x R² = 0.60 y = 1.41x R² = Household size SUMMER WINTER AVERAGE Linear (SUMMER) Linear (WINTER) Linear (AVERAGE) Figure 87: Relationship between household size and average number of loads y = 1.47x R² = Household size FEB MARCH WINTER Average Linear (Average) Figure 88: Relationship between household size and average number of loads (plotting each house individually) Page 77 of 118 Pages

78 Relative frequency In Figure 88 the average number of loads of all the houses have been plotted. This shows clearly the difference between the number of loads, even within each of the different sized household groups. When looking purely at two person households, the minimum number of loads per week is around 1.8 and the maximum is 11. The derived formulae might not be accurate to calculate the number of loads for an individual household, since there is such a wide range within each group, but can be used for calculating this figure for a larger group or sample. For a household size of four and above, the n-value (number of individual homes within each group) gets too small to make generalisations. Table 14 gives a summary of average washing machine use over the two seasonal periods showing that washing machine use has remained fairly constant. Table 14: Washing machine summary SUMMER WINTER Average Stdev Average Stdev Volume/load Loads/day Loads/person/day Litres/house/day Volume/person/day Indoor taps Indoor tap use represents around 12% of total water usage (15% of indoor usage) during summer and 16% (14% of indoor usage) during winter. Overall 213,717 individual events have been recorded from the study homes over the two seasonal periods. 5 45% 4 35% 3 25% 2 15% 1 5% SUMMER WINTER Average Median Stdev Count (n) 143,084 70,633 SUMMER WINTER Seconds Figure 89: Indoor tap use duration summer monitoring period The average use duration was around 25 seconds, with a median of 20 and a standard deviation of 34 seconds (Figure 89) during summer and nearly identical values during winter. As we have used a 10 second monitoring interval, a further breakdown in data Page 78 of 118 Pages

79 Relative frequency would require a shorter logging interval (e.g. 5 seconds). Even if a tap was used for 1 second, the duration would still be recorded as 10 seconds or a use of 11 seconds would be recorded as 20 seconds (10 second increments). Hence, the values for tap use duration are only accurate to ±10 seconds. However, the usefulness of these results is that it can be seen that most tap events have a relatively short duration. Long durations which last several minutes are rare e.g. leaving the tap running while brushing teeth or shaving. 4 35% 3 25% 2 15% 1 5% SUMMER WINTER Average Median Stdev Count 143,084 70,633 SUMMER WINTER Litres Figure 90: Indoor tap use volumes summer monitoring period The volume distribution in Figure 90 shows the amount of water used in each of the individual tap use events. On average 0.9 L of water were used for a single tap event, (median of 0.4 L and a standard deviation of 1.4 L) during summer and a slightly higher average volume of 1.1 L (median of 0.5 and standard deviation of 1.8) during the winter. Thirty-seven percent (33% during winter) of events used 0.25 L of water or less and 9 (86% during winter) used 2.25 L or less during summer. Tap use is a low volume, but high frequency, event as a person uses the tap around 24 times each day during summer and 23 times during winter. The average tap flow rate increased slightly from 2.6 Lpm during summer and 2.9 Lpm during winter (Figure 91). When plotting all individual tap events on a WELS scale (Figure 92), it can be seen that 81% of events would receive a maximum rating of 6 stars during summer and 88% of tap uses would receive this rating over the winter. Only less than 1% of events would receive 1 or 0 stars. From a demand management point of view, reducing Table 15: Tap use summary Average no. tap uses/person Average duration (sec) Average volume/use (L) Average flow rate (Lpm) SUMMER WINTER the flow of taps would not be as feasible, as most taps are already being used at maximum efficient flows, even if they are capable of higher flows. Table 15 shows a summary of tap usage. Page 79 of 118 Pages

80 Relative frequency Relative frequency 3 25% 2 15% 1 SUMMER WINTER Average Median Stdev Count 143,084 70,633 SUMMER 5% WINTER Litres per minute Figure 91: Indoor tap use flow rates summer monitoring period Less than 4.5 Lpm 88% 81% than 4.5 not more than 6 than 6 not more than 7.5 than 7.5 not more than 9 WINTER 9% 4% 4% 3% 3% 3% 2% 1% 1% 6 star 5 star 4 star 3 star 2 star 1 star No star WELS Star Rating than 9 not more than 12 than 12 not more than 16 than 16 Lpm SUMMER Figure 92: Individual tap flows ranked according to WELS Page 80 of 118 Pages

81 > 15 Relative frequency < Relative frequency Toilet Over the two seasonal monitoring periods, a total of 42,290 individual toilet flushes have been recorded. The toilet represents around 23% of the indoor uses during summer and 24% during winter. Figure 93 shows the distribution of toilet flush volumes. The average flush volume (half and full flush was not distinguished) was around 6.6 L per flush during summer and 6.8 during winter. 12% 1 8% SUMMER WINTER Average Median Stdev Count (n) 28,701 13,589 6% 4% 2% SUMMER WINTER Litres Figure 93: Toilet flush volume distribution summer monitoring period 25% 2 15% 1 5% SUMMER WINTER Average Median Stdev SUMMER WINTER Toilet flushes / person /day Figure 94: Average toilet flushes per person per day Page 81 of 118 Pages

82 Relative frequency On average each person would flush the toilet in their home 4.9 times per day during summer and 4.5 times during winter. The flush rate distribution is shown in Figure 94. If plotting the average flush volumes for each home on a WELS scale (Figure 95), it can be seen that the large majority of flush volumes per home have a very low efficiency rating (mainly 0 stars). This was observed in both summer and winter. The adaptation of WELS for reducing water use by toilet retrofit would have an impact on overall water use, especially replacing larger cistern single flush toilets (e.g. 12 L /flush) with more efficient models (e.g. 6 star model) (also see section 8) Not more than 2.5 L than 2.5 not more than 3 than 3 not more than 3.5 than 3.5 not more than 4 than 4 not more than 4.5 than 4.5 not more than 5.5 than 5.5 L 84% 91% SUMMER WINTER 1% 1% 3% 2% 11% 7% 6 stars 5 stars 4 stars 3 stars 2 stars 1 stars 0 stars WELS star rating Leaks Figure 95: WELS star rating (toilets by house) Leakage can have a major effect on a household s water consumption, although larger leaks are generally only found in a minority of houses. During April one of the homes had a leak, which was equivalent to 200,000 L of water during this month. This particular leak increased in size to nearly 10,000 L/d before it was fixed. Leaks are not a seasonal occurrence, but can occur at any time throughout the year and can waste large amounts of water, especially if they are not known to anyone or left ignored. Leaks can include dripping taps and leaking toilet cisterns. Changing worn seals on plumbing appliances can be an important step in demand management Summer leaks Leaks made up 13% of the total water usage (on a household basis 24% on a per person basis) across all the study homes through the February period. During March this share dropped to 6% of total household use (11% of per person use). This drop was mainly due to a large leak being fixed in one of the houses during March. This particular leak was 89% of this home s total use (or 2,301 L/d during February) and dropped to 71% of total uses (or 654 L/d in March). This single leak was responsible for Page 82 of 118 Pages

83 the majority of leaks during the summer period. During February this particular leak represented 77% of all leaks combined. During February, nearly 8 of the homes had leaks, which accounted for less than 1% of their total use, averaging just over 1 L/d. During March this group was reduced to 71%. For the majority of houses the leakage rate remains fairly similar across the two periods. Two other homes have reduced their leakage rate substantially, whereas other homes introduced new leaks. If the major leak (broken water pipe) of this one particular home is disregarded, the overall leakage rate during February and March remained fairly constant, with leaks making up around 3% of the total household uses (around 3 4% of total per person usage). These values for the adjusted summer leaks are identical with data collected in WEEP to one decimal point exactly (3.3%) Winter leaks Leaks represent only 2% of the total water usage across all the study homes throughout the June/July period. This was a substantial reduction to the summer monitoring months. However during the two monitoring periods some homes showed unusually high usage behaviour. After looking at some of the files in detail, it became apparent that these houses had continuous leaks. During April 2008 one home used over 200,000 L (average of 6,700 L/d), as compared to its usual consumption of around 20,000 L. The excess usage was due to leakage as further analysis showed Outdoor Outdoor usage represented around 18% of the total household usage (17% of per person usage) during the summer period and 6% during the winter. The house with the highest usage during summer was also the highest outdoor user during winter. The term outdoor use can include many different individual uses. It includes: irrigation, which is the main outdoor use; the filling and topping up of swimming pools and spa pools; car washing; footpath cleaning; recreation; and other uses. The two houses which had outside swimming pools also had very high outdoor water usage during the whole summer period and slightly lower outdoor usage during winter. One of these houses also had an automatic sprinkler system, which was used for 1 hour on most days during summer, using 900 L during this period. The largest single use outdoor event during the summer had a duration of 6 hours, using a total of 6,362 L in this period. During winter the largest outdoor event had a duration of just under 3 hours and used 2,932 L of water. 6.3 Daily profiles Figure 96 shows the daily water usage profiles of the summer and winter monitoring period. A sharp rise in water flows can be observed at around 6:30 in the morning and at around 17:00 in the evening. These are the main times when people are at home. The peak between 21:00 and 22:00 during the summer is mainly due to the operation of an automatic sprinkler system in one of the properties, which was used nearly daily at the same time. Also the night peak at around 3:00 during summer is also due to an automatic sprinkler system, which was mainly used during February, due to the dry conditions. The maximum average flow was about 41 Lph during summer and 33 Lph during winter. Both summer and winter profiles follow a similar pattern when Page 83 of 118 Pages

84 Average Litres/hour superimposed, the main difference being that more water is used from 19:00 in summer, which is mainly due to a higher outdoor usage SUMMER WINTER :00 02:00 04:00 06:00 08:00 10:00 12:00 14:00 16:00 18:00 20:00 22:00 00:00 Time of day Figure 96: Average daily flow profile summer / winter (10 min averages) When looking at Figure 97 and Figure 98, which compare the daily summer and winter profiles for weekdays and weekend (Saturday and Sunday) respectively, similarities can be seen. The main difference between summer and winter in this case is higher summer water usage after 19:00 on weekdays and 17:00 on weekends. During the week, both summer and winter morning peaks occur at around 6:30 until 8:30. During the weekend this morning peak occurs at around 8:30 until 11:00. During summer the maximum peak flow rate during weekdays is 52 Lph and 50 Lph on weekends. During winter the weekday peak is 45 Lph and 50 Lph on weekends. Page 84 of 118 Pages

85 Average Litres / hour Average Litres/hour SUMMER WINTER 0 00:00 02:00 04:00 06:00 08:00 10:00 12:00 14:00 16:00 18:00 20:00 22:00 00:00 Time of day 60 Figure 97: Average weekday profiles summer / winter (10 min averages) SUMMER WINTER :00 02:00 04:00 06:00 08:00 10:00 12:00 14:00 16:00 18:00 20:00 22:00 00:00 Time of day Figure 98: Average weekend profiles summer / winter (10 min averages) Overall, the daily profiles for summer and winter follow a similar pattern, with the exception of higher evening flows (both weekend and weekdays). This suggests that water use remains fairly constant throughout the year, with a drop in evening outdoor usage during winter. Page 85 of 118 Pages

86 7. COMPARISON BETWEEN AUCKLAND STUDY AND WEEP This section focuses on a water use comparison between this study (Auckland) and WEEP, which looked at water usage in 12 homes on the Kapiti Coast. Monitoring in WEEP was 18 months prior to the Auckland study, but despite this significant similarities can be seen between the two. Table 16 and Table 17 show a summary and comparison of the total and indoor end use distributions. The main difference between the two studies is that there is a slightly higher summer outdoor water usage in the WEEP houses, which could be due to Kapiti s gardening culture and sandy soil types. When looking purely at the indoor use distributions almost no variation can be seen in the share of end uses, except for a slightly higher bathtub usage in WEEP during the winter months. Table 16: Total end use comparison (per person) AUCKLAND WEEP End use Summer Winter Summer Winter Tap 12% 16% 12% 14% Shower 25% 3 22% 27% Washing machine 23% 24% 2 24% Toilet 18% 19% 17% 19% Dishwasher 1% 1% 1% 1% Bathtub 2% 1% 2% 3% Misc 1% Outdoor 17% 6% 22% 8% Leaks 4% 2% 3% 4% TOTAL % 10 Table 17: Indoor end use comparison (per person) End use AUCKLAND WEEP Summer Winter Summer Winter Tap 15.4% 17.8% 16% 15% Shower 31.3% 32.3% 3 31% Washing machine 27.5% 26.5% 27% 27% Toilet % 23% 21% Dishwasher 1.8% 1.4% 2% 1% Bathtub 1.4% 1.4% 2% 4% Misc 0.3% 0.5% 1% TOTAL 100.5% 100.1% % Page 86 of 118 Pages

87 Toilet Taps Washing machine Shower Daily use Gen. Table 18: Summary comparison WEEP / Auckland Entity Units WEEP Auckland (AUK) AUK/WEEP Summer Winter Summer Winter Summer Winter Sample size Houses % 425% Ave. occupancy People Per house Average L % Median L % 87% Stdev L % 101% Max L x x x x Per person Average L % 104% Median L % 10 Stdev L % 107% Max L x x x x Peak demand Average L/day x x x x Median L/day x x x x Stdev L/day x x x x Max L/day x x x x Duration Average min % 91% Median min % 89% Stdev min % Volume Average L % 64% Median L % 59% Stdev L % 84% Flow Average Lpm % 68% Median Lpm % 56% Stdev Lpm % 82% Frequency Average # % 127% Loads/day Average # % Stdev # % 88% Loads/person/day Average # % 12 Litres/day Average L % 9 Stdev L % 74% Litres/person/day Average L % 108% Stdev L % 156% Litres/load Average L % 96% Median L % 95% Stdev L % 10 Duration Average sec % 93% Median sec Stdev sec % 79% Volume Average L % 69% Median L % 71% Stdev L % 69% Flow Average Lpm % 76% Median Lpm % 75% Stdev Lpm % 56% Uses per day Average # % Volume/flush Average L % 109% Median L % 121 % Stdev L % 73% Flushes/day Average # % 92% Median # x x x x Stdev # x x x x (See legend: next page) Page 87 of 118 Pages

88 Code x Legend for Table 18 Range ( ) ; < 8 ; > 12 Not measured / analysed Table 18 shows a detailed summary of parameters measured in both studies. The delta ( ) column shows how the parameters from both studies compare. The closer the figure is to 10 (green), the greater the similarities. The washing machine and toilet usage is almost identical in both cases. During the summer slightly higher water usage, longer shower times and higher shower flow rates were observed in WEEP. It should be noted that WEEP only had a sample size of 12 houses, but the average usage behaviour was very much similar to the data collected from 51 houses in Auckland. If two studies that were conducted independently of each other, at different times, different locations and of different sample size yield such remarkably similar results, the question that arises from this is: Is there an overall water usage similarity between residential homes throughout New Zealand? My answer to this question would be: The results can indicate a trend, but this does not necessarily mean the two samples represent the whole of New Zealand. 8. APPLIANCE UPGRADE The findings from this study conclude that washing machine and toilet replacements are two areas which can achieve large-scale savings. Previously it has been discussed that 84 91% (winter and summer values respectively) of toilets would receive a 0 star rating (more than an average of 5.5 L/flush) under WELS (also see section 6.2.4). Washing machines have not been assessed towards the WELS rating, but many models use relatively high volumes of water (average of 122 L/load). This section examines the potential average savings on a per person basis when existing appliances are being replaced. WaterCare supplies 1.25 million people with water (440,000 households) and treats wastewater from 1 million people (353,000 households) (DeVaal 2008). High water savings can be achieved if large-scale appliance replacements are carried out. 8.1 Toilet savings According to Figure 95 the majority of toilets failed to obtain a star rating under WELS. The average flush volume over the whole monitoring period was 6.7 L/flush (6.6 in summer and 6.8 in winter). On average each person would flush the toilet around 4.7 times (4.9 in summer and 4.5 in winter see section 6.2.4), which equates to a total of 1,716 flushes per person per year, a total of 11,494 L/person/year. Figure 99 shows a flowchart of the relevant water savings per person when replacing the average toilet that is currently installed in the study homes with a more efficient model. This calculation is based on average flush values. As some homes in the study group still have 12 L/flush single flush toilets, the relevant water savings would be higher in these particular homes. Page 88 of 118 Pages

89 If each toilet in Auckland was brought to the standard of a 6 star WELS rated toilet (average of 2.3 L/flush) from the current 0 star average model, the accumulated water savings would be over 9.5 billion L of water per year (7.1% of total yearly supply of 135 billion L) and over 7.6 billion L of wastewater per year, which is around 6.8% of the total wastewater discharge (116 billion L). Lower rated toilets will respectively save less water, due to greater flush volumes. This information is graphically presented in Figure 99. On average each person uses 11,500 L/year for flushing the toilet, which is over 14 billion L/year ( 11% of total water supplied) when looking at the whole population that is served by WaterCare. Current state Target state Units 0 stars star star star star star star WELS rating Toilet volume (L/flush)* Flushes/person/day 1,716 1,716 1,716 1,716 1,716 1,716 1,716 Flushes/person/year 11,494 8,578 2,916 7,291 4,203 6,433 5,061 5,575 5,918 4,718 6,776 3,860 7,634 Litres/person/year Yearly savings (L/p/year) Improved water efficiency and savings *average volumes 1 m 3 = 1000 L Whole Region 1 star 2 star 3 star 4 star 5 star 6 star WATER SUPPLY 3,645,438 5,253,719 6,325,906 7,398,094 8,470,281 9,542,469 Savings (m 3 /year) 9,988 14,394 17,331 20,269 23,206 26,144 Savings (m 3 /day) 2.7% 3.9% 4.7% 5.5% 6.3% 7.1% % of yearly supply WASTEWATER DISCHARGE 2,916,350 4,202,975 5,060,725 5,918,475 6,776,225 7,633,975 Savings (m 3 /year) 2.5% 3.6% 4.4% 5.1% 5.9% 6.6% % of yearly discharge The calculations for the whole region are based on the following data (DeVaal 2008). Total end users Population served (supply side) 1,250,000 Households served (supply side) 440,000 Population served (wastewater side) 1,000,000 Households served (wastewater side) 353,000 Water supply (m 3 /year) 135,050,000 Waste water 2005/06 (m 3 /year) 115,794,000 Figure 99: Toilet retrofits water savings Table 19 shows information on toilet systems found in the study homes. On average each home has 1.6 toilets, which equates to over 700,000 toilets installed in Auckland Page 89 of 118 Pages

90 homes alone (based on number of households served: 440,000). Twenty-seven percent of all toilets in the study group were single flush models, and 31% of households had at least one single flush toilet installed in their house. Fifty-three percent of homes only had one toilet in their home, 35% had two, 8% had three and only 2% had more than three. Table 19: Toilet information Total number of toilets 81 Average number of toilets per household 1.6 Total number of single flush toilets 22 Total number of dual flush toilets 59 Households with one toilet 27 (53%) Households with two toilets 18 (35%) Households with three toilets 4 (8%) Households with more than three toilets 2 (4%) Household with at least one single flush 16 Household with at least one single flush (%) 31% % single flush toilets 27% % dual flush toilets 73% In the study group, 31% of houses still have at least one single flush toilet and of all 81 toilets surveyed, 22 are single flush (27%). This data is shown in Table Washing machine savings The average water use for a single load of washing was measured to be 122 L (section 6.2.2). On average each person would use the washing machine 0.35 times per day (2.5 times per week), which equates to 128 loads/person/year. Figure 100 shows the average water use reduction per person when installing more water efficient washing machines. When replacing the average washing machine (122 L/load) with a 60 L/load machine, around 7,900 L/person/year can be saved. These are average savings, as some households already have more efficient machines, whereas others have machines that use up to 190 L/load. Front-loading machines tend to be more efficient than top-loading ones, even though the efficiency of top loaders is improving. Ninetyfour percent of washing machines in the study were top-loading models. Assuming washing machine habits remain similar if a washing machine is replaced with a more efficient model, high water savings can be achieved. If the average model that is currently installed in Auckland homes (122 L/load) is replaced by an efficient model using 60 L/load, nearly 10 billion L of water could be saved yearly (7.3% of total water supplied) and 7.9 billion L of wastewater (6.8% of total discharge). This is assuming that the water from the washing machine is discharged to the wastewater system, instead of being re-used as greywater. On average each person uses 15,586 L/year for washing machine use alone, which is 19 billion L/year (14% of total water supplied) over the whole population served by WaterCare. Essentially water used by the washing machine can be used as a source of greywater and disposed of on-site, eliminating wastewater volumes. Page 90 of 118 Pages

91 Current state Target state Units , ,775 2, ,220 5, ,665 7,921 litres/load* loads/person/day loads/person/year litres/person/year Yearly savings (L/p/year) Improved water efficiency and savings *average volumes 1 m 3 = 1000 L Whole Region WATER SUPPLY 3,513,125 6,706,875 9,900,625 Savings (m 3 /year) 9,625 18,375 27,125 Savings (m 3 /day) 2.6% % % of yearly supply WASTEWATER DISCHARGE 2,810,500 5,365,500 7,920,500 Savings (m 3 /year) 2.4% 4.6% 6.8% % of yearly discharge Figure 100: Washing machine retrofits water savings 8.3 Shower savings When looking at the shower flow distributions in section 6.2.1, it can be seen that most showers are already obtaining maximum star ratings under WELS. It is the small number of showers in the 0 to 1 star range (13-16% summer/winter respectively) that need to be replaced. The fact that half of all shower events were above a 3 star (maximum) rating shows that either many showers are already efficient in their consumption or the scale to which their efficiency is assessed (WELS) needs to be reexamined. On average, as the data suggest, it is not feasible to retrofit low flow shower heads to random homes, but high savings can be achieved when changing high(er) flow shower heads (12 Lpm or more), which are found in a small number of homes. In these particular homes, high relative water and energy savings (reduced hot water usage) can be achieved, as these homes generally have a much higher proportion of water use in the shower category. Data collected for the Household Energy End-Use Project HEEP (Isaacs et al 2006), shows that 29% of a homes energy usage is for water heating and 77% of New Zealand home s use electricity for this purpose (also see section 0). The shower is the highest hot water user in most homes, and there is a potential to reduce the amount of energy required in individual homes for heating of water, which not only conserves energy, but also reduces greenhouse gas emissions. Page 91 of 118 Pages

92 On average a person would use around 16,800 L/year in the shower alone, which equates to over 21 billion L/year ( 16% of total water supplied) over the whole population. 8.4 Indoor tap savings Figure 92 in section shows the distribution of indoor tap flow rates. The large majority of tap uses are already in the high efficiency range of 5 to 6 stars. Installation of tap aerators or other flow restriction devices on taps would yield minimal results in the study group. However, due to the low cost nature of these devices, short payback periods have been achieved in other studies, even though the water savings were lower than expected (Mayer 2004). It is to be noted that this particular study looks at water conservation in American households, which used nearly twice as much water per person per day than the average New Zealand household. Hence the water savings that have been achieved are much larger and the payback periods are therefore shorter. 8.5 Greywater During the winter period around 63% (min 32%; max 85%) of total household uses could have been reused as greywater, which is the wastewater from showers, washing machines, bathtubs and taps (excluding kitchen taps). During the summer this figure was around 57% (min 23%; max 88%). Greywater makes up a very large proportion of the wastewater that requires treatment. Making use of this alternative water source for garden irrigation, for example, can have a large effect on the total water usage. It is necessary to address this fact, although it is beyond the scope of this project to discuss this option in further detail. 9. DISCUSSION AND CONCLUSIONS The results from this study provide a useful insight into how water is used in Auckland households. By obtaining accurate end-use information, areas in which water can be used more efficiently are able to be identified. 9.1 Key results This section provides a brief summary of the key results discussed in the report. The individual chapters provide a more detailed analysis of the collected data. Retrofitting appliances: In the case of this study, savings can be achieved by installing more water efficient toilets and washing machines. Installation of low flow shower heads would reduce water consumption only in a few houses, as the majority of homes already have relatively low shower flows due to the use of low pressure electric DHW. Reducing the flow of taps (i.e. tap aerators), would have a small effect on reducing water use as 81% of tap uses in summer and 88% in winter already have flows of less than 4.5 Lpm, which is equivalent to a 6 star WELS rating (maximum efficiency). Even though taps are capable of higher flows, the data suggests they are not used to their full capacity. This could be due to the fact that some basins are not designed for high flows as water would spray onto the surroundings. o Toilet replacements: If each toilet in Auckland was brought to the standard of a 6 star WELS rated toilet (average of 2.3 L/flush) from the current 0 star average model, the accumulated water savings would be over 9.5 billion L of water per year (7.1% of total yearly supply of 135 billion L) and over 7.6 billion L of Page 92 of 118 Pages

93 o wastewater per year, which is around 6.8% of the total wastewater discharge (116 billion L). On average each person uses 11,500 L/year for flushing the toilet alone, which is over 14 billion L/year ( 11% of total water supplied) when looking at the whole population that is served by WaterCare. Washing machine replacements: On average each person uses 15,586 L/year for washing machine use alone, which is 19 billion L/year (14% of total water supplied). Assuming washing machine habits remain similar if a washing machine is replaced with a more efficient model, high water savings can be achieved. If the average model that is currently installed in Auckland homes (122 L/load) is replaced by an efficient model using 60 L/load, nearly 10 billion L of water could potentially be saved yearly (7.3% of total water supplied) and 7.9 billion L of wastewater (6.8% of total discharge). This is assuming that the water from the washing machine is discharged to the wastewater system, instead of being reused as greywater. Addressing leaks: Leakage can have a major effect on household water consumption, especially if the leak is unnoticed or left ignored. During February 2008 leaks made up 13% of the total water usage (on a household basis 24% on a per person basis) across all the study homes. This was mainly due to one large leak, which wasted 2,300 L/day. During April 2008 one home had leaks wasting an average of 6,700 L/d (9,000 L/d maximum). Winter measurements showed that leaks represent only 2% of the total water usage across all the study homes throughout this period. The tendency is that only a small number of houses is responsible for the majority of leaks. Leaks still need to be addressed as sometimes it is just a matter of changing a 50 cent seal. It is not always easy for a homeowner to detect a leak. Education programs about water efficiency and leakage control might be the way to go, especially in schools. WELS: There should to be a re-assessment of the WELS star rating bands for taps and showers. Presently installed systems already achieve high ratings, especially in the tap category. This reduces the incentive to improve efficiencies. Indoor usage: The proportion of indoor usage remained fairly constant throughout both summer and winter periods, with a slightly higher volumetric indoor usage during winter. This difference is only small, and when looking at the individual end use components similarities can be seen over the two seasonal periods. This is best represented in Table i and Table ii in the Executive summary. Outdoor usage: Seasonal variation is the main driver for outside usage. During summer, outdoor use represented 17% of the total uses (32 L/p/d), whereas during winter this proportion dropped to 6% (11 L/p/d). Similar to leaks, only a small number of households were responsible for the majority of outside uses in both summer and winter. The highest outside users in the study group were the two houses which had swimming pools and spa pools. Irrigation was the highest single outdoor usage, and these events had a large effect in increasing a household s daily peak demand. The houses with a high outdoor usage during summer also had high outdoor usage during winter. Similarities with WEEP: The data of this study showed remarkable similarities to the data collected from the 12 WEEP houses on the Kapiti Coast. The main difference between the two is a slightly higher summer outdoor usage on the Kapiti Coast. Indoor uses follow a similar pattern for both summer and winter periods of each study, even though there was an 18 month gap between the two studies and the relatively Page 93 of 118 Pages

94 small sample size of WEEP. Does this imply that there are similar water use patterns throughout New Zealand, especially where indoor uses are concerned? The comparison of the two studies is discussed in section 7. Greywater usage: Around 63% of total household water used in winter and 57% used during summer ends up as greywater. Disposing of greywater on a localised scale (e.g. on-site greywater systems) can reduce the amount of water that needs to be supplied and the amount of wastewater that needs to be treated. On average each person in Auckland uses 15,586 L/year for washing machine (greywater source) use alone, which is 19 billion L/year (14% of total water supplied) over the whole population served by WaterCare. Also the shower, which is the largest water user in the average home, is also the largest source of greywater. On average a person would use around 16,800 L/year in the shower alone, which equates to over 21 billion L/year ( 16% of total water supplied and 15% of wastewater volumes) over the whole population. Accumulated water savings: If each toilet in Auckland was brought to the standard of a 6 star WELS rated toilet (average of 2.3 L/flush) from the current 0 star average model, the accumulated water savings would be over 9.5 billion L of water per year (7.1% of total yearly supply of 135 billion L) and over 7.6 billion L of wastewater per year, which is around 6.8% of the total wastewater discharge (116 billion L). On average each person uses 11,500 L/year for flushing the toilet alone, which is over 14 billion L/year ( 11% of total water supplied) when looking at the whole population that is served by WaterCare. 9.2 Next steps Sixty-two percent of Auckland s water usage is in the domestic sector (WaterCare 2006). The unique data set collected in this project provides a detailed picture of how water is used in this area, and can help to understand where improvements and changes can be made to improve the overall functionality of the whole system. Before changes can be made it is important to understand this. The data can be used in water demand management models, or individual models can be constructed from it. 9.3 Last words If each home in Auckland is brought up to a higher efficiency status than at present, large cumulative savings can be made when looking at the whole population. As previously mentioned, Auckland s population is increasing at twice the national average, which is also increasing the strain on the water infrastructure and the environment. Water efficient technology has already been available for many years; it now needs to be used to upgrade the building stock for a more sustainable future. Page 94 of 118 Pages

95 10. REFERENCES Aquacraft Inc. TraceWizard Water Use Analysis Software ( accessed 10/10/2008). DeVaal D Personal Correspondence. WaterCare Services Limited, Newmarket, New Zealand. Heinrich M Residential Water End Use Literature Survey. BRANZ Study Report 149. BRANZ Ltd, Judgeford, New Zealand. Heinrich M Water End Use and Efficiency Project (WEEP) Monitoring Report. BRANZ Study Report 159. BRANZ Ltd, Judgeford, New Zealand. Heinrich M Where is Auckland s Water Going?. BUILD Magazine (April/May 2008, Issue 105, page 54). Heinrich M. 2008a. Auckland Water Use Study (AWUS) Report on the Summer 2008 End Use Monitoring Period. BRANZ Ltd, Judgeford, New Zealand. Isaacs et al Energy Use in New Zealand Households: Report on the Year 10 Analysis for the Household Energy End-use Project (HEEP). BRANZ Study Report 155. BRANZ Ltd, Judgeford, New Zealand. Ministry of Consumer Affairs (MCA) Proposed Implementation of Mandatory Water Efficiency Labelling. MCA, Wellington, New Zealand. Mayer P et al Tampa Water Department Residential Water Conservation Study. Aquacraft Inc., Boulder, Colorado, USA. Pollard A Personal Correspondence. BRANZ Ltd, Judgeford, New Zealand. Statistics New Zealand, 2006 Census, ( accessed 9 June 2008). WaterCare Asset Management Plan. WaterCare Services Limited, Newmarket, New Zealand. Page 95 of 118 Pages

96 APPENDIX A EQUIPMENT Page 96 of 118 Pages

97 BRANZ Pulse Logger P84 The BRANZ pulse logger has been designed as a large capacity data logging solution for the collection and storage of meter count intervals. The original use of the logger was in the Household Energy and Efficiency Project (HEEP). It has successfully been used for nearly eight years, in various monitoring applications. For our water monitoring project this logger has been modified to suit the pulse output from high resolution water meters (e.g. 50 pulses per litre) at a ten second interval. The Logger, when connected to a pulse output (e.g. water meter) counts and stores the pulse total for each logging interval. Different intervals can be selected, ranging from 2 seconds to 60 minutes. Pulse input USB communication The logger connects to a PC via an USB cable. The Windows standard Hyper Terminal software is used for communication with the logger. The logger is powered by an alkaline 9V battery, which lasts more than 3 months when 10 second data is collected. Specifications: Memory: Dimensions: Number of channels: Recording Intervals: Power Supply: Weight (incl. battery): Weight (without batteries): Logging: 321,480 records including daily timestamps at 10 second interval (38 days data of 1 channel, 12 bit ) 95 x 60 x 25 (mm) 1, 2, or 4 channels 2, 10 seconds 1, 2, 3, 4, 5, 6, 10, 15, 20, 30, 60 min 9 V Alkaline (PP3) 120 g 65 g Max. count rate 40Hz Selectable 12 bit (4095 counts/interval) or 16 bit (65535 counts/interval) Page 97 of 118 Pages

98 APPENDIX B SAMPLE FLOW TRACE The following diagram shows an example of a leaking toilet valve from a flow trace. The x-axis represents time and the y-axis flow. Green represents the toilet flush and blue represents the continuous leak. In some instances these leaks can have a significant impact on overall water usage, especially if leaks are continuous. Toilet flush Leak Page 98 of 118 Pages

99 APPENDIX C FLOW BANDS This section summarises the winter data in flow bands of litres per hour (Lph). Figure 101 shows a graph of the data presented in Table 20. Table 20: End use flow distribution (litres per hour) L/hour TAP SHOWER WASHING M TOILET IRRIGATION LEAKS % 0.1% % 0.9% 98.9% % % 0.4% 0.9% % % 0.6% 0.3% 0.1% % 0.1% % 0.5% % 2.6% 2.1% 3.9% 3.3% % 19.3% 0.4% 9.7% 11.8% % 22.4% 2.7% % % 17.5% 3.5% 13.8% 9.5% % 10.7% 10.7% 13.6% 5.7% % 9.2% 26.5% % % % 4.2% % 4.5% 14.3% 3.6% % 4.9% 10.9% 2.3% 9.9% % 1.3% 9.4% 3.2% 7.8% % 3.5% 2.4% 9.3% % 1.9% 1.2% 3.4% % 0.5% 4.2% % 0.5% 2.2% % % 0. Page 99 of 118 Pages

100 TAP SHOWER 3 2 WASHING MACHINE TOILET 3 2 OUTDOOR 1 Litres / hour Figure 101: Water flows in litres/hour Page 100 of 118 Pages

101 APPENDIX D MAILOUT INFORMATION Page 101 of 118 Pages

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