The U.S. Environmental Protection Agency (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).