Released Final Fourth Regulatory Determination and Proposed Fifth Unregulated Contaminant Monitoring Rule (UCMR 5) Today the U.S. Environmental Protection Agency (EPA) announced that two steps in the Safe Drinking Water Act (SDWA) regulatory process have been reissued following a review by the new administration: Final regulatory determinations for eight contaminants, with positive determinations for perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS) Proposal for the UCMR 5 , including monitoring for 29 individual per-and polyfluoroalkyl substances (PFAS) and lithium These actions represent the new administration’s previously noted interest in protecting drinking water. Action early in 2021 on both items is important for EPA to meet statutory timeframes set in SDWA. Neither action creates an immediate regulatory requirement for public water systems, but both set the stage for the development of future requirements, particularly with respect to drinking water standards and monitoring for PFAS. Final Fourth Regulatory Determinations The final regulatory determination notice, once published in the Federal Register , will constitute a final agency action. In the notice, EPA is communicating that it will: Pursue regulating PFOS and PFOA in drinking water, and Not regulate 1,1-dichloroethane, acetochlor, methyl bromide (bromomethane), metolachlor, nitrobenzene, and Royal Demolition eXplosive (RDX). Not make a determination for any other CCL contaminants, including strontium, 1,4-dioxane, and 1,2,3-trichloropropane (1,2,3-TCP). These findings are consistent with the preliminary regulatory determinations proposed in March 2020 and will initiate a 24-month deadline for the agency to propose drinking water regulations for PFOA and PFOS. EPA’s notice repeatedly notes the potential health risk associated with PFOA and PFOS for sensitive life stages including fetuses, newborns, infants and young children. Fifth Unregulated Contaminant Monitoring Rule Proposal UCMR 5 is intended to improve EPA’s understanding of how frequently, and at what concentrations, 29 PFAS and lithium occur in finished drinking water in the nation’s public water systems. EPA will accept public comment on the proposed UCMR 5 for 60 days from the date of publication in the Federal Register . EPA anticipates finalizing UCMR 5 and moving rapidly into preparatory activities with laboratories and water systems in 2022 with field sampling beginning in 2023. The 29 PFAS included in the notice are those quantified using EPA Methods 533 and 537.1 , which is consistent with a requirement in the National Defense Authorization Act for Fiscal Year 2020 that EPA include all PFAS for which it had a validated analytical method in UCMR 5. Unlike previous UCMR cycles, if Congress appropriates adequate funding, all community water systems serving 3,300 – 10,000 persons will be required to monitor in UCMR 5. EPA is taking this step in response to provisions of the America’s Water Infrastructure Act of 2018. Information is not yet available whether the required funding will be available. EPA is also requesting comment on including other specific analytes in UCMR5: Legionella pneumophila , four haloacetonitriles, 1,2,3-TCP, and total organic fluorine. Water systems should anticipate media attention not only on the inclusion of PFAS but also lithium. Last week, the United States Geology Survey (USGS) announced a recent study that found lithium in 9% of public water supply wells were above 60 µg/L, USGS's drinking-water-only health reference level concentration. Questions can be directed to Chris Moody , regulatory technical manager, or Greg Kail , director of communications.