The State of U.S. Urban Water: Data and the Energy-Water Nexus

Data on urban water resources are scarce, despite a majority of the U.S. population residing in urban environments. Further, information on the energy required to facilitate the treatment, distribution, and collection of urban water are even more limited. In this study, we evaluate the energy-for-water component of the energy-water nexus by providing and analyzing a unique primary database consisting of drinking water and wastewater utility flows and energy. These anthropogenic fluxes of water through the urban environment are used to assess the state of the U.S. urban energy-water nexus at over 160 utilities. The average daily per person water flux is estimated at 560 L of drinking water and 500 L of wastewater. Drinking water and wastewater utilities require 340 kWh/1,000 m³ and 430 kWh/1,000 m³ of energy, respectively, to treat these resources. The total national energy demand for water utilities accounts for 1.0% of the total annual electricity consumption of the United States. Additionally, the water and embedded energy loss associated with non-revenue water accounts for 9.1 × 10⁹ m³ of water and 3,100 GWh, enough electricity to power 300,000 U.S. households annually. Finally, the water flux and embedded energy fluctuated monthly in many cities. As the nation's water resources become increasingly scarce and unpredictable, it is essential to have a set of empirical data for continuous evaluation and updates on the state of the U.S. urban energy-water nexus.