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REGULATORY EXPLAINER
EPA PFAS Rule 2027: What Private Well Owners Need to Know
In April 2024, the EPA finalized the first federal limits on PFAS in drinking water. Public utilities have until 2027 to monitor and until 2029 to comply. Private well owners are not covered. But this rule still matters for you.
Last reviewed: May 2026
What the 2024 rule set
The EPA published its final PFAS rule on April 10, 2024 under the Safe Drinking Water Act. It is the first time federal law has set a specific limit for PFAS in drinking water. The limits (called maximum contaminant levels, or MCLs) are:
| Compound | Federal MCL | Notes |
|---|---|---|
| PFOA | 4 ppt | Most studied PFAS compound. Found near Teflon manufacturing sites. |
| PFOS | 4 ppt | Used in firefighting foam (AFFF). Common near military bases. |
| PFBS | 10 ppt | Short-chain PFAS, sometimes used as a replacement for PFOS. |
| GenX (HFPO-DA) | 10 ppt | Used by Chemours in NC. Contaminated Cape Fear River basin. |
| PFNA + PFHxS | Mixture limit | Regulated together under a hazard index calculation. |
Source: EPA PFAS information page
Who the rule applies to
The rule covers public water systems: utilities serving 25 or more people. About 66,000 public systems across the US fall under this rule.
Private wells are not included. The Safe Drinking Water Act has always treated private wells as the responsibility of the owner, not a public concern. That has not changed.
But the rule matters for well owners for one key reason: it establishes 4 ppt as the safety benchmark for PFOA and PFOS. If your well tests above that, you now have a clear context for what it means. Before April 2024, there was no federal reference point.
The 2027 deadline explained
Public utilities have two deadlines. By 2027, they must monitor for the six regulated PFAS compounds and report results publicly. By 2029, they must have reduced levels to below the MCL if initial monitoring finds violations.
The 2027 monitoring requirement is what most people refer to when they say "EPA PFAS rule 2027." This is the year when a large amount of PFAS data from water utilities becomes publicly available.
For well owners, this means 2027 will bring new contamination maps and publicly accessible data that can help you understand what is in your area. Testing now gives you a pre-2027 baseline.
States going further than the federal rule
Some states adopted PFAS limits before the federal rule. Others went stricter than the EPA MCL. A few extended monitoring to private wells.
Vermont
MCL of 20 ppt total PFAS. Mandatory testing in some private well zones.
Michigan
Some of the strictest individual compound limits in the US. Active private well monitoring near contaminated sites.
New Jersey
1 ppt limit for PFNA (far stricter than federal). Private well testing requirements in contamination zones.
Massachusetts
Combined PFAS6 limit of 20 ppt. One of the earliest states to act on PFAS before the federal rule.
California
Adopted state MCLs aligned with the federal rule. Active testing program through State Water Board.
Maine
Mandatory PFAS testing for private wells within a mile of agricultural fields where PFAS-contaminated biosolids were applied.
Connecticut
8 ppt limit for PFOA and PFOS, stricter than the federal 4 ppt MCL on a combined basis.
Washington
DOH adopted advisory levels ahead of the federal rule and runs public education programs for well owners.
New York
10 ppt limit for PFOA and PFOS adopted before the federal rule. Active monitoring near contaminated sites.
Illinois
Illinois EPA adopted interim advisory levels and is tracking private well exposure near PFAS sites.
What to do now as a well owner
Test your well for PFAS before 2027. This gives you a baseline so you can compare against the new public utility data when it comes out. If your well is already above 4 ppt, you want to know now, not in two years.
Use a certified lab. Basic strip tests cannot detect PFAS at these levels. A comprehensive panel costs $150 to $300 and tests 32 or more compounds.
If results are above 4 ppt, see our guide on what to do after a positive PFAS test.
Frequently asked questions
Does the EPA PFAS rule apply to private wells?
No. The 2024 EPA PFAS rule covers public water systems only. Private well owners are not legally required to meet the 4 ppt limit. But the limit now gives you a clear benchmark to judge your own results against.
What is the EPA limit for PFAS in drinking water?
The EPA set maximum contaminant levels (MCLs) in April 2024. PFOA and PFOS must each be below 4 parts per trillion. PFBS and GenX (HFPO-DA) are capped at 10 ppt. PFNA and PFHxS are regulated under a mixture calculation that considers combined exposure.
When do public water systems have to comply?
Public utilities have until 2027 to monitor and report PFAS levels and until 2029 to meet the MCLs if action is required. The 2027 date is when widespread monitoring data will become publicly available.
Which states have stricter PFAS rules than the federal standard?
As of 2026, Vermont, Michigan, New Jersey, Massachusetts, and California all have state PFAS standards that are equal to or stricter than the EPA federal rule. Vermont and New Jersey have also extended some monitoring requirements to private wells.