H.R. 4168 — PFAS National Drinking Water Standard Act of 2025

This section codifies the Environmental Protection Agency's (EPA) final rule titled “PFAS National Primary Drinking Water Regulation” (89 Fed. Reg. 32532; April 26, 2024), as in effect on June 25, 2024, giving it the force and effect of law. (The rule establishes national primary drinking water standards—including maximum contaminant levels (MCLs) of 4.0 ppt for PFOA and PFOS, 10 ppt for PFNA, PFHxS, and HFPO-DA (GenX), and a hazard index for PFBS, PFHxS, HFPO-DA, and PFNA mixtures—for per- and polyfluoroalkyl substances (PFAS), or "forever chemicals," in public water systems.)