Summary Report - Waterwise

1 Summary Report The Residential End Use of Water Project BACKGROUND Understanding when, where, and why water is used in a household can provide vital information for the development of effective water demand management strategies. Detailed knowledge of the quantities of water used in different household activities provides data that can inform planning, forecasting and water conservation initiatives that traditional long-term average consumption patterns may fail to provide. In Abu Dhabi, the residential sector consumes a significant amount of the desalinated water that is produced for the Emirate. Therefore, understanding how water is being used in a home is an important focal point for water sustainability efforts. To this end, The Residential End Use of Water (REUW) Project is the first of its kind in the country and aims to collect and analyse water end-use data in unprecedented detail.

2 THE PROJECT The Project involved the installation of high-resolution meters in 150 medium sized villas in gated communities located in Abu Dhabi. These meters capture flow trace signatures from individual appliances and fixtures within the villa. The data was then downloaded to a flow trace analysis software (Trace Wizard ) that showed how water was being used around the home. In addition, a water use behavioural survey was carried out on participating residents to further complement metered data, helping us analyse specific patterns and learn more about participants habits and perspectives regarding their own water use. The REUW Project was designed to achieve the following objectives: collect accurate statistics of residential water use: where and how consumers actually use water within their homes; investigate the socio-demographics of water-use in Abu Dhabi, which groups generally use the most and least water, and how each group uses water; determine the split between indoor and outdoor water-use in the Abu Dhabi environment; identify and explore the scale of water leaks, which are costly and may be wasting significant amounts of water; and inform decisions and strategies for future water management and conservation programmes in Abu Dhabi.

3 The first stage of the REUW Project took place from September to October, 2012, and involved a small-scale pilot study that allowed us to test each component of the project in the Abu Dhabi context. The pilot phase enabled us to test our processes, check any potential areas of concern and ensure the minimum inconvenience to project participants going forward into the full-project stages. The full Project commenced in the first quarter of 2013 with the recruitment of 150 participants and subsequent installation and surveying. RECRUITMENT AND INSTALLATION Recruitment of 150 volunteers was carried out using a door-knocking approach at pre-selected compounds. Potential participants were provided with an information brochure so they could understand the project s aim and timeline.

4 This helped us recruit those interested in participating in this project. A compulsory demographic and basic water-use survey was filled out by each willing participant. Following recruitment, a high-resolution water flow meter and data logger, capable of remotely transferring data, was installed at each villa. The smart meter was installed in the pipe downstream of the individual household storage tanks and booster pumps, as shown in Figures 1 and 2. Figure 1: illustration of REUW project equipment installation Page 2 of 7 Figure 2: Smart meter and data logger in roof top SITUATIONAL CONTEXT Project participants were successfully recruited from 9 compounds in Abu Dhabi. Locations of the compounds are shown in Figure 3. Figure 3: General location of compounds All of the smart meters capture indoor water consumption; however, some compounds have an alternative irrigation supply or automatic pool top-up which by-passes the smart meter installed as part of the REUW Project.

5 Two examples of compound-specific outdoor garden arrangements are shown in figures 4 &5. Figure 4: Garden with outdoor tap and sprinkler system Figure 5: Public grass area supplied by compound irrigation and private garden watered by outdoor taps FLOW TRACE ANALYSIS The study used data obtained from water meters and data loggers attached to the outlets of the roof tanks that supplied the domestic water to the homes. The data from the water meters was collected at 10 second intervals with a resolution of litres per pulse. At this resolution it was possible to disaggregate the water use in the homes into individual water use events, and to categorise the events by end-use. This allowed the research team to determine household and per- capita water use directly from the participant s meter in a non-intrusive manner, and in a way that eliminated uncertainties caused by leakage in the distribution system or the storage tanks.

6 Page 3 of 7 1004007001,0001,3001,6001,9002,2002,5002 ,8003,1003,4003,700moreRelative Frequency1%12%28%31%13%8%5%0%1%1%0%0%0%1 %Cumulative Frequency1%13%40%72%85%93%97%97%98%99%99 %99%99%100%0%10%20%30%40%50%60%70%80%90% 100%0%5%10%15%20%25%30%35%FrequenciesDom estic Use (LPD)Relative FrequencyCumulative FrequencyFigure 6 shows an example of what the flow trace data look like on the screen during analysis. The key to the process is that events fall into repeating patterns, which the programme recognises and labels. Each water use event in the flow trace was characterised by fixture type, flow rate, duration and volume. Figure 6: A trace with identical parameters for one of the toilets and one cycle of a clothes washer BREAKDOWN OF END USES Water consumption results Following the three monitoring periods, the flow trace signatures logged at each villa were disaggregated and analysed to match flow patterns with water use events and specific water using appliances.

7 The key findings from combined monitoring periods are summarised below. Overall study group Table 1 summarises the per-household water use statistics from the study group for the combined monitoring periods. Table 1: Water use for combined monitoring periods in litres per household per day Parameter Total use Domestic use Landscape Leakage Mean 95% 1679 200 882 81 673 147 124 83 Median 1208 788 284 522 Std. Deviation 1256 511 924 12 Percent of total for combined monitoring periods 100% 53% 40% 7% The average household indoor use excluding leakage is 882 litres per day, with leakage accounting for of the total household water use as shown in figure 7 Figure 7: Average daily household use breakdown during the combined monitoring periods in litres per household per day Figure 8 shows a histogram of the average daily indoor water use from the homes for the combined monitoring periods.

8 The data show that half of the homes used between 700 and 1,000 litres per household per day (excluding leakage). Figure 8: Distribution of domestic use during the combined periods Per-household breakdown Table 2 summarises the average household water use statistic. Table 2: Average water end-use consumption per household for combined monitoring periods End use Average (litres per household per day) Total 1,679 Domestic 882 Landscape 673 Bathtub 14 Clothes washer 111 Dishwasher 3 Tap 345 Leak 124 Other 2 Shower 213 Toilet 195 Page 4 of 7 breakdown Per capita use is largely driven by the number of occupants residing in each home. The average number of household occupants was The overall average daily indoor water consumption for the study group was 168 litres per capita per day, as shown in Table 3.

9 This value was derived by dividing the total water consumption for the study group by the total number of live-in participants. Table 3: Average water end-use consumption per capita for combined monitoring periods End Use Average (litres per capita per day) Total 340 Domestic 168 Landscape 149 Bathtub 3 Clothes washer 21 Dishwasher Tap 64 Leak 23 Other Shower 41 Toilet 38 Discussion by end use Indoor end uses Figure 9 is a pie chart showing the percentage of each end use for domestic purposes for the combined monitoring periods. Generally, the per-capita use was very consistent between the three monitoring periods, with the exception of the landscape use category. Of note is the fact that the average leakage rate for the homes is greater than water use for clothes washers.

10 However, it is important to highlight that large leaks in a small number of homes have skewed the results, as is referred below. Figure 9: Breakdown of domestic end uses by household during the combined monitoring periods Miscellaneous tap use Tap use includes a wide range of applications: from dish washing and plant watering to car washing, and to every type of miscellaneous use around the home that requires water. Overall tap use accounted for an average of 345 litres per day in the homes. This represents 21% of the total water use and 34% of the domestic water use in these homes during the study period. On average, each home used a tap 132 times per day with frequent, short duration. Figure 10 shows the distribution of tap events by their duration.