Meeting future water needs for the United States will likely require increased energy inputs to meet water quantity and quality requirements. Current water infrastructure will need to respond to both changes in population distribution and new regulatory requirements to remove contaminants of emerging concern. Additionally, current water resources may become fully tapped and deteriorate in quality, particularly with climate change increasing the severity of droughts, changing rainfall patterns, and increasing seawater levels. Thus, a future water portfolio will likely include greater quantities of water that is brackish, saline, and from contaminated sources, as well as water located farther from point of use or reused from different wastewater sectors. Together, this means future water supply will require greater inputs of energy to access, treat, and transport to end-users. Our work models the future energy requirements for water treatment, using a combination of regional and national datasets on current and projected domestic water requirements. We examine state- and county-level water resource plans to determine how different regions are responding to the pressures of climate change, and where current water supply may fall short of projected demand. This analysis was done in conjunction with modeling energy efficiency and decarbonization in wastewater. Finally, we estimate future carbon emissions associated with water and wastewater treatment, considering both the anticipated changes in treatment technologies and grid decarbonization. This work aims to inform nation-wide strategies for both meeting future water needs and anticipating the associated energy requirements.
