Sensitivity of residential water consumption to variations in climate: An intraurban analysis of Phoenix, Arizona

Water remains an essential ingredient for the rapid population growth taking place in metropolitan Phoenix, Arizona. Depending upon the municipality, between 60 and 75% of residential water is used outdoors to maintain nonnative, water-intensive landscapes and swimming pools. Residential water use in Phoenix should be especially sensitive to meteorological and climatic variations because of the strong emphasis on outdoor water use. This study explores the intraurban spatial variations in the sensitivity of residential water consumption to atmospheric conditions. For 230 census tracts in the city, we developed times series of monthly water use anomalies and compared them with monthly anomalies of temperature, precipitation, and the Palmer Drought Hydrological Index. We found that one third of census tracts have little to no sensitivity to climate, while one tract had over 70% of its monthly variance in water use explained by atmospheric conditions. Greater sensitivity to atmospheric conditions occurred in census tracts with large lots, many pools, a high proportion of irrigated mesic landscaping, and a high proportion of high-income residents. Low climatic sensitivity occurred in neighborhoods with large families and many Hispanics. Results suggest that more affluent, non-Hispanic neighborhoods will be disproportionately affected by increasing temperatures due to urban heat island effects and the buildup of greenhouse gases.