On 14 May, 2025, the U.S. Environmental Protection Agency announced it will retain the existing Maximum Contaminant Levels (MCLs) of 4 parts per trillion (ppt) for PFOA and PFOS under the National Primary Drinking Water Regulations (NPDWR). At the same time, the agency plans to revisit the regulatory determinations for four additional PFAS compounds—PFHxS, PFNA, GenX (HFPO-DA), and PFBS—along with the Hazard Index standard originally set for mixtures of these substances. These changes follow the agency’s earlier final rule issued in April 2024, which introduced enforceable limits for six PFAS and marked the first use of a Hazard Index in federal drinking water regulation.
The EPA signaled plans to extend the compliance deadline for PFOA and PFOS from 2029 to 2031 and establish a federal exemption framework for certain drinking water systems. A proposed rule is expected in the fall of 2025, with a final rule targeted for the spring of 2026. Meanwhile, litigation over the original PFAS NPDWR remains active in the District of Columbia Circuit Court, and additional regulatory updates are anticipated as the EPA continues to roll out components of its broader PFAS policy plan.
