Assessment of household water use efficiency using performance indices

Abstract This paper presents a novel methodology for evaluating the efficiency of indoor household water use based on performance assessment functions that convert state variables (e.g., flow rate, volume) into performance indices, considering efficient flow rates or volumes of the most common water use devices. Performance indices are dimensionless and range from 0 (the lowest performance) to 300 (excellent performance). An overall household water use index is calculated from the individual water use device indices by weighting each device in accordance with the water end use consumption breakdown. The application of this methodology to 43 households enabled the quantification of potential water savings and the identification of device-specific measures to increase the water use efficiency. In addition, a clustering analysis of performance indices and households’ characteristics provided evidence of the existence of relationships between household water use efficiency and socio-demographic variables. The outcomes of this study and the application of the proposed efficiency indices allow demand managers to better tailor urban water conservation strategies to most water use devices and to groups of consumers with specific socio-demographic characteristics.