PFAS — "per- and polyfluoroalkyl substances," often called "forever chemicals" — are a large family of industrial compounds that resist breaking down. EPA regulates a handful of them in public drinking water. The rule is real, but it is also actively changing, so the useful thing is to know what is settled, what is only proposed, and what you can do no matter how it lands.
What is final: the 2024 PFAS rule
On April 10, 2024, EPA finalized the first national drinking-water limits (Maximum Contaminant Levels, or MCLs) for six PFAS:
| PFAS | Limit (MCL) |
|---|---|
| PFOA | 4 parts per trillion (ppt) |
| PFOS | 4 ppt |
| PFHxS | 10 ppt |
| PFNA | 10 ppt |
| GenX (HFPO-DA) | 10 ppt |
| Mixtures of the above (plus PFBS) | Hazard Index of 1 |
Under the 2024 rule, public water systems must complete initial monitoring by 2027 and meet the limits by April 26, 2029. These limits apply to public water systems — not private wells.
What is proposed (May 2026 — not final)
On May 18, 2026, EPA proposed two changes. Both are proposals, open for public comment through July 20, 2026 (with a virtual hearing on July 7, 2026):
- Keep PFOA and PFOS at 4 ppt, but let systems request two extra years — moving the compliance deadline from April 26, 2029 to April 26, 2031.
- Rescind the limits for the other four — PFHxS, PFNA, GenX, and the Hazard Index mixture — and reconsider them.
Until those proposals are finalized, the 2024 limits and the 2029 deadline remain on the books. But the timing and scope may change, which is exactly why you will see conflicting "2029 vs 2031" and "six PFAS vs two PFAS" claims online. The durable core is the PFOA and PFOS limit of 4 ppt.
What it means for you
- On public water: your utility must test for these PFAS and, over time, treat if levels are too high — though the deadline may slip to 2031 and four of the limits may be pulled back. Check your annual water report (CCR) and ask your utility whether PFAS were detected.
- On a private well: this rule does not cover you at all. If you have reason to suspect PFAS — near industrial sites, airports or military bases (firefighting foam), or certain manufacturing — test through a certified laboratory.
- Either way, you do not have to wait for a federal deadline. A filter certified for PFAS reduction can reduce PFOA/PFOS at your own tap now.
How to reduce PFAS at your tap now
- Reverse osmosis systems certified to NSF/ANSI 58 for PFAS reduction are one strong point-of-use option.
- Some activated-carbon filters certified to NSF/ANSI 53 with a specific PFOA/PFOS reduction claim also work — verify the exact model, because "filters water" is not a PFAS claim. See verified PFAS-filter picks, NSF 53 vs 58, and whether a Brita helps.
- Do not rely on boiling as a PFAS treatment method; EPA points consumers to certified filtration instead.
This is regulation in motion. We date this page and update it as EPA finalizes or changes the proposals above.