US officially moves to dismantle drinking water PFAS regulations

By Rebecca Trager | Chemistry World | May 21, 2026

Read the full article by Rebecca Trager (Chemistry World)

"Having announced its intentions in May last year, the US Environmental Protection Agency (EPA) hasnow formally proposed new rules limiting drinking water levels for six per- and polyfluoroalkyl substances (PFAS).

In 2024, president Joe Biden put in place the first ever national, legally enforceable drinking water standards to protect US communities from exposure to PFAS. They set limits at 4 parts per trillion (ppt) for the two most well-known substances, perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS), and 10ppt for four other PFAS chemicals – perfluorohexane sulfonate (PFHxS), perfluorononanoic acid (PFNA), PFBS, hexafluoropropylene oxide-dimer acid (HFPO-DA, or GenX), and mixtures of these three, plus perfluorobutane sulfonic acid (PFBS) – under the US Safe Drinking Water Act.

In May 2025, EPA administrator Lee Zeldin announced that the agency intended to allow water companies two additional years (until 2031) to comply with the 4ppt limits on PFOS and PFOA, and completely repeal the limits on the remaining substances. At the time, experts told Chemistry World there was no scientific reason to reverse these limits, and that doing so would be a ‘tremendous setback to common sense water stewardship’."