The Safe Drinking Water Act (SDWA) requires that once every five years EPA issue a list of unregulated contaminants to be monitored by public water systems (PWSs).
The fifth Unregulated Contaminant Monitoring Rule (UCMR 5) was published on December 27, 2021. UCMR 5 requires sample collection for 30 chemical contaminants between 2023 and 2025 using analytical methods developed by EPA and consensus organizations. This action provides EPA and other interested parties with scientifically valid data on the national occurrence of these contaminants in drinking water. Consistent with EPA’s PFAS Strategic Roadmap, UCMR 5 will provide new data that is critically needed to improve EPA’s understanding of the frequency that 29 PFAS (and lithium) are found in the nation’s drinking water systems and at what levels. This data will ensure science-based decision-making and help prioritize protection of disadvantaged communities.