Building Water-Efficient Cities: A Comparative Analysis of How the Built Environment Influences Water Use in Four Western U.S. Cities

Problem, research strategy, and findings: Cities across the United States must have reliable and consistent water supplies to support public health, promote economic growth, and protect the environment. The way we build and design cities influences water consumption patterns; however, the most significant factors of the built environment and their associations with water use are not well explored. In this study we seek to reveal the ways in which characteristics of the built environment influence urban water use. We analyze spatially detailed data sets of water use and the built environment in four different cities in the western United States. Our findings indicate the built environment in these cities has a substantial influence on single-family residential water use. Specifically, we find that vegetated land cover, housing density, and lot size are influential determinants of water use. However, we did find variation in the strength and significance of these variables between the cities, and there remains a need for city-specific analyses. Takeaway for practice: The results indicate even small changes to design and permitting for single-family residential properties can produce substantial cumulative water savings for cities. Based on our findings, we propose planning and design strategies such as form-based codes, zoning, and municipal ordinances to help growing cities reduce their water use. We present estimates of the water conservation impacts these strategies might achieve and provide specific examples of planning documents, municipal ordinances, and land use plans some cities are already using to reduce their water use. Overall, our study provides empirical evidence to further support integrating land use planning and water management.