The U.S. EPA has published the Fifth Unregulated Contaminant Monitoring Rule (UCMR 5). 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 presence of these contaminants in drinking water. PFAS are included in the UCMR.