Investigation of domestic water end use

Abstract

[Abstract]: This project explores domestic water end use and investigates water consumption in ten households in Toowoomba to determine a methodology for a possible future expansion of study, incorporating a larger number of residential houses. Water restrictions, rebate programs and WaterWise education form the essential elements of water demand management in Toowoomba but little is known about the effectiveness of these programs and the actual impact they have on per capita water use – particularly on individual end uses over time. Reliable measurements of water savings are essential to determine the impacts of conservation projects on urban water demands. Other factors that affect water consumption, demand patterns and peaking factors are also investigated. The information can be used to educate the community and promote their participation in water conservation activities and behaviours. The basic methodology of the project was as follows: A sample of 10 households was selected to be fitted with high resolution water meters and data loggers. The data on water use in these households were collected every 10 seconds for a continuous period of 138 days. This data was then analysed and disaggregated into relevant end use categories using Trace Wizard software. The average water consumption for the ten households under study was found to be 112 litres/capita/day, which is well under the Level 5 water restrictions target of 140 L. It was found that the implementation of water restrictions had changed the peaking factors for Toowoomba significantly and these need to be taken into account for planning purposes. Showers contribute to the largest end water use amounting to 43.5% with washing machines using the second largest amount at 22.7%. Volume used by showers (and other flow based devices) was governed by the flow rate from the showerhead (Low Flow, Ultra Low Flow or Normal), the duration spent in the shower (7.2 minutes on average) and the number of events/capita/day, which was inversely related to the number of children present in the household. The total volume used by washing machines (and other volume based devices) was governed by the volume used per cycle and the number of cycles/capita/day. It was found that front load washers used less than half the amount of water as top loading washers. Water restrictions have significantly decreased the average demand of water. This is evident through the lack of a seasonal pattern due to residential water being used solely for indoor purposes. The provision of rebates for water efficient devices by both the State Government and Toowoomba Regional Council are currently targeted to the areas where they are likely to save the most water. The uptake of these water efficient devices from the ten households under study was good with 60% of households having the most water efficient devices installed. WaterWise education was highlighted as a significant and essential part of demand management programs with changes in consumer’s behaviours likely to save the most water when compared to retrofitting of water efficient devices. The information from this study will be used to educate the community and promote their participation in water conservation activities and behaviours. This project supports the sustainable use of the region’s scarcest resource and will have major implications for demand management programs in Toowoomba and across Australia.