Impacts of water efficient appliances on the design of the water supply infrastructure

Abstract

Water efficient appliances are proven measures of reducing householders’ peak water demand on cities’ mains water supply network and consequently provide benefits to the water provider, in terms of augmentation deferrals and reduced sized infrastructure. However, while acknowledged in the literature, the actual benefits have not been thoroughly investigated and quantified. The paper aims to demonstrate how the installation of water efficient appliances would affect the design of the water supply network. Using an updated methodology incorporating end-use data from smart water meter, peak day water demand profiles were developed for the baseline scenario (Scenario A), representing the typical building code mandated for new dwellings constructed in the region of Queensland, Australia, and for households fitted with higher efficiency water appliances (Scenario B). Hydraulic model runs were conducted for both scenarios over various planning horizons to determine the scheduling of augmentations in a water supply study area in South East Queensland. The results of the model runs showed deferred and eliminated augmentations as well as a reduction in infrastructure sizing for Scenario B in comparison to Scenario A. The resulting monetary savings from installing higher efficiency water appliances in the study area represented 11.4% of total original augmentation costs, with the majority of savings due to deferred network augmentations. The paper concludes with the implications of reduced peak demands on the water infrastructure network and the potential for additional financial benefits to be realised by the water utility.