PFAS ("Forever Chemicals") in Drinking Water

Who this page is for

Homeowners who've heard the term "PFAS" or "forever chemicals" and want the plain-English version

PFAS regulation has changed more in the past two years than almost any other area of drinking water law, and it's still actively changing as of this page's last review. This guide explains what PFAS are, what's currently regulated, and what's actually happening with the rules right now — without the alarmist framing that usually surrounds this topic.

The basics

What PFAS actually are

PFAS (per- and polyfluoroalkyl substances) are a large family of manufactured chemicals in use since the 1940s, valued for their resistance to heat, water, and oil. That's why they've historically shown up in non-stick cookware coatings, water-resistant and stain-resistant fabrics, some food packaging, and firefighting foam used at airports and military and industrial sites. The same chemical stability that makes them useful also makes them very slow to break down in the environment and in the human body — the source of the "forever chemicals" nickname.

PFAS can enter drinking water sources near manufacturing sites, airports, military installations, and other locations where they were historically used, and are now monitored nationally as part of ongoing EPA drinking water programs.

Current regulation

EPA's 2024 national drinking water standard

On April 10, 2024, EPA finalized the first-ever National Primary Drinking Water Regulation for PFAS, setting enforceable Maximum Contaminant Levels for six specific compounds:

• PFOA and PFOS: 4.0 parts per trillion (ppt) each — regulated individually
• PFHxS, PFNA, and HFPO-DA (GenX): 10 ppt each — regulated individually
• Mixtures containing two or more of PFHxS, PFNA, HFPO-DA, and PFBS: a Hazard Index limit (a combined-risk calculation with a target of 1.0) rather than individual numeric limits

Under the original rule, public water systems must complete initial monitoring by 2027, install treatment where needed by 2029, and begin public notification of any violations starting in 2029.

What's changing right now

EPA's May 2026 proposed changes

In May 2026, EPA proposed two significant changes to this framework, both open for public comment through July 20, 2026 (a public hearing was held July 7, 2026):

• A compliance extension: water systems could request two additional years — until 2031 instead of 2029 — to meet the PFOA and PFOS limits. The 4.0 ppt limits themselves would not change.
• A proposed rescission: EPA proposed withdrawing the drinking water regulations for PFHxS, PFNA, HFPO-DA (GenX), and the Hazard Index mixture limit, stating this is necessary to correct what it describes as a procedural failure to properly follow Safe Drinking Water Act rulemaking requirements when those specific standards were set in 2024. Notably, EPA has indicated it may propose to re-regulate these same substances in the future through a corrected process, potentially with different limits.

As of this page's last review, these are proposed rules, not final — the PFOA and PFOS limits remain in effect at 4.0 ppt, and no rescission has yet taken legal effect. Given how actively this area is changing, check EPA's own PFAS page for the current status before relying on any specific compliance date.

What this means for you

What to actually do about PFAS today

• Check your provider's most recent CCR for a PFAS results section — many systems have already tested under EPA's nationwide UCMR5 monitoring program or the 2024 PFAS rule specifically
• If you're on a private well, PFAS testing is your own responsibility — a certified lab can test specifically for PFAS compounds
• If you want additional reduction regardless of your test results, look for filtration certified under NSF/ANSI 53 or NSF/ANSI 58 with a specific PFAS reduction claim — our under-sink reverse osmosis guide covers how these systems work
• Don't assume a single "not detected" result means permanent certainty — PFAS monitoring is ongoing, and results can be re-checked in future reports

Common mistakes

Mistakes to avoid

• Assuming all PFAS regulation was rescinded because of the May 2026 proposals — the PFOA/PFOS limits remain in place today
• Treating a proposed rule as already final — proposed rescissions and extensions go through a public comment process before taking effect
• Buying a filter without checking its specific PFAS reduction certification — not all filtration removes PFAS effectively
• Skipping your CCR's PFAS section because the term feels unfamiliar — it's usually listed plainly alongside other tested substances

When to get help

When to get professional help

If your CCR shows a PFAS detection, you're on a private well near a known industrial or airport site, or you simply want a treatment option evaluated specifically for PFAS reduction, a local water treatment provider can test your water and recommend equipment with a verified PFAS certification.

Official sources

Official source links

• EPA: PFAS National Primary Drinking Water Regulation
• EPA: Proposed PFOA and PFOS Compliance Extension Rule
• EPA: Proposed PFAS Rescission Rule

FAQ

Frequently asked questions

What does PFAS stand for, and why are they called "forever chemicals"?

PFAS stands for per- and polyfluoroalkyl substances, a large group of manufactured chemicals used since the 1940s in products like non-stick cookware, water-resistant fabrics, and firefighting foam. They're called "forever chemicals" because their chemical structure makes them extremely resistant to breaking down in the environment or the human body.

Which PFAS are currently regulated in drinking water?

Per EPA's 2024 PFAS National Primary Drinking Water Regulation: enforceable limits were set for six PFAS — PFOA and PFOS at 4.0 parts per trillion (ppt) each, and PFHxS, PFNA, and HFPO-DA (GenX) at 10 ppt each, plus a Hazard Index limit for mixtures containing two or more of PFHxS, PFNA, HFPO-DA, and PFBS.

What changed with EPA's May 2026 proposals?

Per EPA's May 2026 proposed rule: EPA proposed two things — first, an option for water systems to request two additional years (until 2031) to comply with the PFOA and PFOS limits, without changing those limits; second, a proposal to rescind the drinking water regulations for PFHxS, PFNA, HFPO-DA, and the Hazard Index mixture, citing procedural concerns with how those specific standards were originally established. EPA has said it may re-regulate these same substances later through a different process.

Does this mean my water isn't being checked for PFAS right now?

Not necessarily — even with the proposed changes, PFOA and PFOS limits remain in place, and many systems have already begun monitoring under EPA's 2024 rule and the separate UCMR5 nationwide monitoring program. Check your provider's CCR for PFAS results specific to your water.

Last reviewed: July 9, 2026