Resumen
Water reuse, the beneficial use of highly treated municipal wastewater (reclaimed water), is expanding throughout the United States (U.S.); however, there are currently no federal reclaimed water use regulations, only guidelines. As a result, state policies on reclaimed water vary widely, emphasizing the need for a comprehensive understanding to facilitate coordinated national planning. Our systematic literature review, utilizing an online legal research database, presents an updated overview of U.S. reclaimed water policies from 2004 to 2023. A novel categorization scheme tracks policy changes, highlighting a 38% increase in states regulating reclaimed water between 2004 and 2023. We also created maps of current reclaimed water use regulations across the U.S. including: (1) a national overview of the reclaimed water policy landscape; and (2) documentation of non-food crop and food crop irrigation policies. As of November 2023, 74% of states (37/50) intentionally regulated reclaimed water use. Regions with historically low water scarcity, such as the Midwest, exhibited lower participation rates in reclaimed water regulation than water-scarce regions in the West. Of the 37 states regulating direct reclaimed water use in 2023, all allowed for at least some agricultural uses; 23 permitted non-food and food crop production use, while 14 states have statutory allowances for direct reclaimed water use on non-food crop production. As climate change stresses freshwater resources, our work provides up-to-date information for policymakers to navigate existing reclaimed water use policies.