The 2024 PFAS limits for tap water: what EPA kept and what it proposed to drop in 2026

On April 10, 2024, the U.S. Environmental Protection Agency announced the first national, legally enforceable limits on PFAS in drinking water. They cover six of the chemicals often called "forever chemicals" in water supplied by public water systems across the United States. Since then the agency has changed course on part of it. It has kept the limits for PFOA and PFOS, but in May 2026 it proposed giving water systems until 2031 to meet them and proposed repealing the limits for the other four. Those are proposals only: the 2024 rule is the one in force.

What the 2024 rule set

The rule was published in the Federal Register on April 26, 2024, and took effect on June 25, 2024. It set two numbers for each substance: a maximum contaminant level, the enforceable limit, and a maximum contaminant level goal, a health-based target that is not enforceable. Compliance is judged on running annual averages at each sampling point.

The rule set a timetable. Public water systems must complete initial monitoring by April 26, 2027, and begin telling the public about PFAS levels in their water that year. Systems with levels above the limits have until April 26, 2029, to bring them down; from then on, a system in violation must act to reduce PFAS and notify the public.

At the time, EPA estimated that 4,100 to 6,700 water systems would be affected by the limits, and that over many years the rule would prevent PFAS exposure for about 100 million people. Its analysis put the quantified benefits at $1,549.40 million a year and the quantified costs at $1,548.64 million, at a 2% discount rate, and projected 29,858 fewer illnesses and 9,614 fewer deaths in the decades after PFAS levels fell. EPA noted that those modeled figures were nearly at parity and said the law required it to weigh unquantified costs and benefits as well.

The 2025 change of course

In a news release in May 2025, EPA Administrator Lee Zeldin said the agency would keep the PFOA and PFOS limits while offering "common-sense flexibility in the form of additional time for compliance." EPA said it planned to propose moving the compliance date for those two to 2031 and to set up a federal exemption framework. It also said it intended to rescind the limits for PFHxS, PFNA, HFPO-DA and the mixture, and to reconsider them so that any regulation followed the process the Safe Drinking Water Act lays down.

The release quoted two water-sector groups in support. The executive director of the Association of State Drinking Water Administrators said states and water systems "are struggling with the timeframes" for testing, design and construction under the 2029 date.

The two proposals of May 2026

EPA announced both proposals on May 18, 2026, and they were published in the Federal Register on May 20. The first would let systems that apply for a federal exemption meet the PFOA and PFOS limits by April 26, 2031, instead of April 26, 2029. The limits themselves would stay at 4.0 parts per trillion, and the monitoring and reporting deadlines of the 2024 rule would not move. Systems granted the extra time would have to tell their customers, and any with a PFOA or PFOS result at or above 12 parts per trillion would have to take short-term steps to cut exposure in the meantime. EPA argues that many systems need more time to gather data, choose treatment, arrange financing and build, and that violations in the meantime would not speed up health protection.

The second proposal would remove the limits for PFHxS, PFNA, HFPO-DA and the mixture. EPA now says the 2024 rule broke the law's step-by-step process, because the agency proposed and finalized its decisions to regulate these substances at the same time as the regulation itself. It says the proposal rests solely on that legal point, not on any reassessment of the findings behind the limits, and it is not taking comment on health risks, costs or occurrence. EPA estimates that dropping the PFHxS limit would save $11.6 million a year in 2022 dollars and reduce previously expected benefits by about $6.7 million. Asked whether it will regulate the same PFAS in future, EPA says that once the rescission is final it will take steps to evaluate PFAS in drinking water for future regulation, and that "it is possible that the result could be more stringent requirements."

The rule is also in court. EPA's May 2026 proposal says its 2024 determinations and parts of the regulation are the subject of pending litigation, American Water Works Association v. EPA, No. 24-1188, in the U.S. Court of Appeals for the District of Columbia Circuit.

What applies today

The comment periods on both proposals closed on July 20, 2026, after a virtual public hearing on July 7. EPA's pages still describe both as proposed rules, and a search of the Federal Register on November 11, 2026, found no final rule on either. Until EPA finalizes one, or a court rules otherwise in the pending case, the 2024 rule stands as written, including the April 2027 monitoring deadline and the April 2029 compliance date for all six limits.

For anyone concerned about their own water, EPA's advice is to contact the drinking water system to find out its PFOA and PFOS levels and what it is doing about them. Under the 2024 rule, community water systems must give customers their PFOA and PFOS results "annually or biannually," in EPA's words, and EPA suggests people concerned about their own health risk talk to a doctor.