PFAS drinking water rule argued in court; 2024 limits still in effect
Are the EPA PFAS limits for drinking water still in effect?
The D.C. Circuit heard arguments on September 18, 2026 in the utilities' challenge to EPA's 2024 PFAS drinking water rule; EPA's May 2026 proposals to change the rule are not final, so the 4 ppt PFOA and PFOS limits and the 2029 deadline still stand.
American Water Works Association v. EPA (No. 24-1188) challenges the April 2024 rule that set limits for six PFAS, including 4.0 ppt each for PFOA and PFOS. Arguments on September 18, 2026 covered how EPA sequenced its decisions, the occurrence data behind a national rule, the Hazard Index for PFAS mixtures, and costs.
In January 2026 the court refused EPA's request to vacate the parts of the rule it no longer defends, and it later declined to hold those issues in abeyance.
Separately, on May 20, 2026 EPA published two proposals: one would let water systems request until 2031 to meet the PFOA and PFOS limits; the other would rescind the limits for PFHxS, PFNA, HFPO-DA (GenX) and the Hazard Index mixture. Comments closed on July 20, 2026. Neither is final.
Until a court ruling or final rule changes it, the 2024 rule remains in effect: initial monitoring is due by April 26, 2027 and compliance with the limits by April 26, 2029.
Home filters can be certified for PFAS under NSF/ANSI 53 or 58, either for PFOA/PFOS or for a 7-PFAS 'Total PFAS' claim.
Filters in this update
