EPA is finalizing a Safe Drinking Water Act (SDWA) rule that requires certain public water systems (PWSs) to collect national occurrence data for 29 per- and polyfluoroalkyl substances (PFAS) and lithium. Subject to the availability of appropriations, EPA will include all systems serving 3,300 or more people and a representative sample of 800 systems serving 25 to 3,299 people. If EPA does not receive the appropriations needed for monitoring all of these systems in a given year, EPA will reduce the number of systems serving 25 to 10,000 people that will be asked to perform monitoring. This final rule is a key action to ensure science-based decision-making and prioritize protection of disadvantaged communities in accordance with EPA's PFAS Strategic Roadmap. EPA is also announcing plans for public webinars to discuss implementation of the fifth Unregulated Contaminant Monitoring Rule (UCMR 5). This final rule is effective on 26 January 2022. The incorporation by reference of certain publications listed in this final rule is approved by the Director of the Federal Register as of 26 January 2022. POC is Brenda D. Bowden, Standards and Risk Management Division (SRMD), Office of Ground Water and Drinking Water (OGWDW) (MS 140), EPA, 26 West Martin Luther King Drive, Cincinnati, Ohio 45268; tel: (513) 569-7961; email: bowden.brenda@epa.gov.

(Federal Register 27 December 2021 [Rule] Pages 73131-73157).