Learnings from Municipal Water Use Characterization in the Contiguous United States

Abstract:

This study investigated municipal water use patterns across the contiguous United States (CONUS). Specifically, the objectives of the study were to explore temporal trends in water use, and to improve characterization of commercial, industrial and institutional (CII) water use in cities within the CONUS. Monthly water use data were obtained from 126 municipalities for the period 2005 – 2017 with specific information about residential and CII water use categories. Water use trends and levels of water conservation were statistically analyzed using the gallons per capita day (GPCD) as the assessment metric. The changes in CII to Residential water use ratio were related to physiographic and socioeconomic factors such as climate, city population, and employment is various sectors. Results indicate an overall decreasing trend in municipal water use with higher reductions achieved in residential water use. Both residential and CII water use show high seasonality over an average year. The CII to Residential ratio increases with city population and is highest in cities in the Northeast census region. Cities in South and West census regions have high municipal water demand but also show relatively high rate of reduction in per capita water demand by year. Cities in arid climate have the highest water demand compared to other cities due to landscape irrigation. Using multivariate analysis, April precipitation, annual vapor pressure deficit, number of employees in manufacturing sector, and total percentage of houses built before 1950 and total percentage of single-family houses, are identified to explain the CII to Residential water use ratio in the CONUS.