Estimating and Verifying Household Potential to Conserve Water

This paper identifies impacts of behaviors and technology on residential indoor water use and conservation efforts. We use pre-existing detailed end-use data collected when toilets, faucets, showerheads and clothes washers were retrofitted in 96 owner-occupied, single-family households in Oakland, CA, Seattle, WA, and Tampa, FL. between 2000 and 2003. Water volume, duration of use, and time of use were logged and disaggregated by appliance for two weeks before and four weeks after appliances were retrofitted. For each appliance, we compare observed differences in water use before and after retrofits to water savings predicted by analytical engineering and econometric regression methods. Results show that observed and predicted distributions of water savings are skewed with a smaller number of households showing potential to save more water. Results also show the relative influence on water saved of technological (flow rates of appliances) and behavioral (length of use, frequency of use) factors. Study results help improve engineering methods to estimate water savings from retrofits and allow water utilities to better target subcategories of households that have potential to save more water.