Analysis of Fixture Efficiency and Behavioral Factors of Indoor Residential Water Use of Single‐Family Households

Abstract This study examines indoor water use patterns in single‐family households by analyzing commonalities and differences between household water use categories, the relative importance of fixture efficiency versus behavioral factors in explaining water use and its differences between household categories, and the correlation of pronounced weather events, house characteristics, and household size on efficiency and behavioral factors. Using unprecedented high‐resolution smart meter data from 33,435 households across 39 major US cities, we find distinct geographical clustering of high water‐using households in southwestern, southern, and north‐central US, with these households possessing more water‐intensive appliances. In contrast, low water‐using households cluster in coastal areas, particularly California. While behavioral factors explain most variation in total per capita indoor water use, fixture efficiency better differentiates between high and low water‐using households, particularly around clothes washer end use. Efficient clothes washers and reduced toilet use offer the greatest potential to close the gap between high and low water‐using households. We find significant economies of scale in total per capita water use and behavior factors around toilet and shower, where per capita consumption decreases as household size increases. Pronounced weather events significantly correlate with water use behaviors, particularly around toilet and shower. These findings suggest that sustainable urban water management strategies should combine targeted fixture efficiency improvements with behavioral interventions, focusing on high water‐using households where the greatest conservation potential exists.