PFAS Limits by State: The Question That Suddenly Matters
In May 2026, the EPA proposed keeping its drinking water limits for two PFAS compounds and pulling back the limits for four others. Since that announcement, one question keeps coming up: what does my state actually allow?
It's the right question, and the answer depends on your address more than most people expect. PFAS limits by state run from 4.0 parts per trillion (ppt) up to six-figure values for certain compounds, and most states have no state limit at all. PFAS regulations by state are a patchwork laid over a federal floor, and the seams are exactly where the confusion lives.
This page is the full reference: every enforceable state PFAS limit in the country as of July 2026, each verified against the agency's own published rule, plus the federal baseline that covers everyone else. One thing it is not: a map of where PFAS has been detected. That is a different question, and our PFAS contamination map answers it.
Key Takeaways
A Federal Floor for Everyone
Ten States Set Their Own
Four Federal Limits in Limbo
No Limit Is Not No PFAS
How PFAS Drinking Water Limits Work
A PFAS limit is a maximum contaminant level (MCL): the highest concentration of a contaminant legally allowed in the water a public water system delivers to your tap. Exceed it and the utility has a violation, with public notice and treatment obligations to follow.
PFAS (per- and polyfluoroalkyl substances) are a group of synthetic chemicals engineered to resist heat, oil, and water. That same durability is why they persist in the environment and in people, and why regulators measure them in parts per trillion. For the full backstory on how they reach your faucet, see our guide to PFAS in tap water.
Enforceable, Proposed, or Guidance: Know Which Number You're Reading
Not every PFAS number you'll come across carries legal weight. There are three tiers, and mixing them up is the single most common mistake in this topic:
- Enforceable MCL: adopted law. A confirmed exceedance is a violation with real consequences for the water system.
- Proposed: a number moving through rulemaking. Nothing binds until the rule is final.
- Guidance or advisory: a health-based reference point. Useful for context, but nobody is required to meet it.
Every value in the table below is either an enforceable state MCL or a federal MCL a state has formally adopted, and each row says which.
The Federal Floor: PFOA and PFOS at 4.0 ppt
Under the EPA's PFAS National Primary Drinking Water Regulation, PFOA and PFOS each carry an enforceable federal MCL of 4.0 ppt, with a health goal of zero. Public water systems nationwide must comply by April 26, 2029. A separate May 2026 proposal (Federal Register document 2026-10086) would let a system request an extension to April 26, 2031; it was not final as of July 2026.
Federal and state limits stack the way minimum wages do. The federal government sets a floor, states are free to demand more, and the more protective rule is the one that counts where you live. With MCLs, more protective means lower.
There's a timing wrinkle, though. A state MCL can be enforceable today while a stricter federal number is still phasing in toward that 2029 compliance date. New Jersey is the cleanest example: its 14 ppt PFOA limit binds utilities right now, while the federal 4.0 ppt limit works through the federal timeline.
Four Federal Limits Are in Limbo
On May 20, 2026, EPA published a proposed rule to rescind the federal MCLs for PFHxS, PFNA, HFPO-DA (better known as GenX), and the Hazard Index covering mixtures of those three plus PFBS. Proposed is the operative word. All four limits stay enforceable unless a final rule removes them, and the public comment period runs through July 20, 2026.
Here's the part most people miss: rescinding a federal limit doesn't touch state limits for the same compounds. New Hampshire, Michigan, Vermont, and Wisconsin each regulate at least one of the four in state law, and New Jersey's PFNA limit plus the Massachusetts, Maine, and Rhode Island sum standards cover them too, and those numbers stay put no matter what happens in Washington. We walk through the federal side in detail in our companion piece on EPA's PFAS drinking water regulations.
PFAS Regulations by State: The 2026 Limit Table
Ten states enforce their own PFAS MCLs as of July 2026: New Jersey, New York, New Hampshire, Michigan, Massachusetts, Maine, Rhode Island, Vermont, Pennsylvania, and Wisconsin. Delaware and Illinois enforce the federal limits through state adoption. Every value below was verified against the named state agency (linked on each state) on July 19, 2026. Rules move, so if your state has adopted something newer, its drinking water program will have it first.
ppt means parts per trillion, the same as nanograms per liter (ng/L). For scale, one part per trillion is about one penny out of ten billion dollars. The Hazard Index is different: it's a unitless score for PFAS mixtures, and a total above 1 is an exceedance.
| State | Regulated PFAS and enforceable limit (ppt) | Status | The nuance |
|---|---|---|---|
| Federal baseline (all states) | PFOA 4.0; PFOS 4.0; PFHxS 10; PFNA 10; HFPO-DA (GenX) 10; Hazard Index 1 (unitless) | Enforceable federal MCLs; PFOA and PFOS compliance by April 26, 2029 | EPA has proposed rescinding the PFHxS, PFNA, GenX, and Hazard Index limits (not final as of July 2026) |
| New Jersey | PFOA 14; PFOS 13; PFNA 13 | Enforceable state MCLs | First state to set a PFNA MCL; the stricter federal PFOA and PFOS limits phase in on the federal timeline |
| New York | PFOA 10; PFOS 10 | Enforceable state MCLs (adopted 2020, 10 NYCRR Subpart 5-1) | The 10 ppt limits stay the operative numbers until the federal 4 ppt MCLs take over in 2029; a June 2026 bill to lower and expand them awaits the governor's signature, so it is pending, not law |
| New Hampshire | PFOA 12; PFOS 15; PFHxS 18; PFNA 11 | Enforceable state MCLs | Written into state law by HB 1264 (2020); NHDES says its PFHxS and PFNA standards are unaffected by the federal proposal |
| Michigan | PFNA 6; PFOA 8; PFOS 16; PFHxS 51; HFPO-DA (GenX) 370; PFBS 420; PFHxA 400,000 | Enforceable state MCLs | Seven compounds, the most of any state; the PFHxA value really is 400,000 ppt; private wells are not covered |
| Massachusetts | Sum of six PFAS (PFOA, PFOS, PFHxS, PFNA, PFHpA, PFDA): 20 combined | Enforceable state MCL (MMCL) | One combined standard, not per-compound; MassDEP has until April 26, 2028 to adopt rules at least as strict as the federal MCLs |
| Maine | Sum of six PFAS (PFOA, PFOS, PFHxS, PFNA, PFHpA, PFDA), alone or in combination: 20 | Enforceable interim state standard (2021) | Holds until April 26, 2027, when Maine's by-reference adoption of the federal MCLs takes effect; the standard also covers schools and child care facilities on their own supplies |
| Rhode Island | Total PFAS (sum of PFOA, PFOS, PFHxS, PFNA, PFHpA, PFDA): 20 combined | Enforceable state MCL (final, effective September 18, 2024) | Missing from most trackers; grew out of a 2022 interim law, and systems that exceeded it entered consent agreements that carry forward under the final rule |
| Vermont | PFOA 4.0; PFOS 4.0; PFHxS 10; PFNA 10; HFPO-DA 10; Hazard Index 1 (unitless) | Enforceable state MCLs (effective January 1, 2026) | Matches the federal numbers but stands on its own in state rule, so it survives a federal rescission; replaced the older combined 20 ppt standard |
| Pennsylvania | PFOA 14; PFOS 18 | Enforceable state MCLs | Only PFOA and PFOS are state-regulated; compliance is a running annual average at each entry point |
| Wisconsin | PFOA 4.0; PFOS 4.0; PFHxS 10; PFNA 10; HFPO-DA 10; Hazard Index 1 (unitless) | Enforceable state MCLs (effective July 1, 2026) | Replaced the 2022 combined 70 ppt PFOA plus PFOS standard; kept all six parameters despite the proposed federal rescission |
| Delaware | PFOA 4; PFOS 4; PFHxS 10; PFNA 10; HFPO-DA (GenX) 10; Hazard Index 1 (unitless) | Federal MCLs, adopted by reference | No state-specific MCLs; a 2022 state proposal was never promulgated, so Delaware's numbers track the federal outcome |
| Illinois | PFOA 4; PFOS 4; PFHxS 10; PFNA 10; HFPO-DA (GenX) 10; Hazard Index 1 (unitless) | Federal-identical state MCLs (final January 22, 2026) | Wrote the federal numbers into state regulation as identical-in-substance rules, so a final federal rescission could force conforming amendments; timeline mirrors federal |
The Early Movers: New Jersey, New York, New Hampshire, Michigan, Massachusetts, Pennsylvania
These six states didn't wait for a federal rule.
New Jersey moved first in the nation on PFNA back in 2018, then finished MCLs for PFOA (14 ppt) and PFOS (13 ppt) in 2020, per the New Jersey Department of Environmental Protection. NJDEP says it's working to fold the newer federal requirements into state regulation. Until that happens, 14, 13, and 13 are the binding state numbers.
New York holds the biggest audience for the timing question. The state adopted MCLs of 10 ppt for PFOA and PFOS in 2020 under 10 NYCRR Subpart 5-1, and the New York State Department of Health is explicit that systems must keep meeting those 10 ppt limits until the federal 4 ppt standards take over in 2029. Same layering as New Jersey: the state number binds today, the federal number arrives on the federal clock. One thing to watch: the Legislature passed a bill in June 2026 that would lower those numbers and extend limits to more PFAS, but as of July 2026 it awaited the governor's signature. Pending, not law.
New Hampshire set four MCLs through 2019 rulemaking and then wrote them into law with House Bill 1264 in July 2020: PFOA 12, PFOS 15, PFHxS 18, and PFNA 11 ppt, per NHDES. In its April 2026 regulations update, the department said plainly that its PFHxS and PFNA standards will not be affected by the federal rescission proposal.
Michigan regulates seven compounds, the most of any state, under rules from the Department of Environment, Great Lakes, and Energy: PFNA 6, PFOA 8, PFOS 16, PFHxS 51, HFPO-DA (GenX) 370, PFBS 420, and PFHxA at 400,000 ppt. That last one isn't a typo. One catch worth knowing: Michigan's rules cover public water systems, not private residential wells, though the state uses the same values when evaluating well results.
Massachusetts took a different approach entirely: one combined limit of 20 ppt for the sum of six PFAS (PFOA, PFOS, PFHxS, PFNA, PFHpA, and PFDA), in effect since October 2020, per MassDEP. The standard is still in effect, and MassDEP has until April 26, 2028 to adopt rules at least as stringent as the federal MCLs. Expect this one to evolve.
Pennsylvania regulates two compounds: PFOA at 14 ppt and PFOS at 18 ppt, adopted in 2023 under the Pennsylvania DEP's PFAS MCL Rule. Compliance is judged on a running annual average at each entry point, so one bad quarter can tip a system into violation.
The Sum Standards: Maine and Rhode Island
Maine caps six PFAS (PFOA, PFOS, PFHxS, PFNA, PFHpA, and PFDA) at 20 ppt, alone or in combination, an interim standard the Legislature set in 2021 that is enforceable right now, per the Maine CDC Drinking Water Program. Exceed it and treatment or other remedies must follow. Two things make Maine unusual. Its standard reaches beyond community systems to schools and child care facilities on their own supplies, and the state recommends the same 20 ppt figure to private well owners as guidance. It also has an expiration date: Maine has adopted the federal PFAS rule by reference, so the federal MCLs replace the interim standard on April 26, 2027.
Rhode Island slipped past most trackers, but its MCL is final: 20 ppt for total PFAS, the same six compounds as Massachusetts and Maine, effective September 18, 2024 in the state's public drinking water regulations (216-RICR-50-05-1), per the Rhode Island Department of Health. It grew out of a 2022 interim law that required every public water system to sample. Systems that exceeded the standard entered consent agreements with the health department, and those carry forward under the final rule.
The 2026 Adopters: Vermont and Wisconsin
Vermont and Wisconsin both rewrote their rules recently, and both did something quietly significant: they took the federal numbers and made them state law. PFOA and PFOS at 4.0 ppt, PFHxS, PFNA, and HFPO-DA at 10 ppt each, and a Hazard Index of 1 for mixtures.
Why does that matter? Because a standalone state MCL survives a federal rescission. Vermont's Water Supply Rule, effective January 1, 2026, specifically carves PFAS out of the state's usual defer-to-federal clause. If you've seen the older Vermont standard of 20 ppt for five combined PFAS, that's history; the individual MCLs replaced it.
Wisconsin's ch. NR 809, effective July 1, 2026, replaced the state's 2022 combined 70 ppt PFOA plus PFOS standard and kept all six federal parameters in state code even after EPA proposed dropping four of them. Wisconsin systems must complete compliance monitoring by April 26, 2027 and meet the MCLs by April 26, 2029.
Delaware and Illinois: The Federal Numbers, State-Enforced
Delaware is the one state in this table without state-specific MCLs. Instead, it applies the federal values as they stand: PFOA and PFOS at 4 ppt, PFHxS, PFNA, and GenX at 10 ppt, and a Hazard Index of 1, per the Delaware Division of Public Health (June 2026). A 2022 state proposal was never promulgated.
What Delaware added in 2025 is a transparency law. Senate Bill 72, effective January 2026, requires the Division of Public Health to publish PFAS levels online and requires notification when a system exceeds an MCL. It's a reporting law, not a new limit.
Illinois reached the same destination by a different route. Instead of pointing at the federal rule, the Illinois Pollution Control Board wrote the federal numbers into state regulation as identical-in-substance MCLs, final January 22, 2026, per the Illinois EPA: PFOA and PFOS at 4 ppt, PFHxS, PFNA, and GenX at 10 ppt, and a Hazard Index of 1, on the federal monitoring and compliance timeline. Because identical-in-substance rules track federal law, a final federal rescission could force conforming amendments, though the state EPA has publicly committed to keeping its PFAS protections.
What If Your State Is Not on the List?
If your state isn't in the table, the federal MCLs are your numbers. PFOA and PFOS at 4.0 ppt apply to every public water system in the country, with compliance required by April 26, 2029, and the four limits in the rescission proposal remain enforceable unless EPA finalizes their removal.
Two caveats belong here.
First, this table tracks enforceable MCLs only. The near-misses matter: California's PFOA and PFOS notification levels are explicitly non-regulatory with an MCL still in rulemaking, Washington uses action levels rather than MCLs, and many other states rely on guidance or advisory values that don't carry the force of law. A missing row means your state had no enforceable PFAS MCL as of July 2026, not that nobody in your state capital is working on one. Your state drinking water program is the first place to check for anything newer.
Second, and more important: no limit is not the same as no PFAS. A state without an MCL isn't a state with clean water; it's a state that hasn't set a number yet. If you want to know what's actually in your glass, the ground truth is a test. Our guide to PFAS water testing covers how to do it and what the results mean.
MCLs generally bind public water systems, not private wells. Maine comes closest to an exception: its 20 ppt standard covers schools and child care facilities on their own supplies, and the state recommends the same number to homeowners as guidance. For everyone else on a well, testing and treating your water is your call, and in your control.
What You Can Do at Home, Whatever Your State Allows
Here's the empowering part: household filtration doesn't care which row of the table you live in. The technologies that reduce PFAS work by function, and the physics is the same in New Jersey as in a state with no MCL at all.
Three technologies do the real work:
- Activated carbon adsorbs PFAS, meaning the molecules stick to the carbon's vast internal surface as water passes through.
- Ion exchange uses resin beads that attract and hold PFAS molecules, trading them out of your water.
- Reverse osmosis (RO) pushes water through a semipermeable membrane that rejects PFAS along with a wide range of other dissolved contaminants.
When you compare systems, the benchmarks to look for are NSF/ANSI 53 (health-related reduction claims, including PFOA and PFOS) and NSF/ANSI 58 (reverse osmosis system performance). Those standards exist so you don't have to take anyone's word for it.
Where the equipment goes matters too. A point-of-use (POU) system treats water at a single tap, usually the kitchen, and under-sink RO is the classic PFAS answer there. A point-of-entry (POE) system treats water where it enters the house, so showers, laundry, and every faucet see filtered water.
Crystal Quest has been designing and manufacturing multi-stage filtration systems in the USA for over 30 years, and a PFAS-focused setup usually comes down to under-sink reverse osmosis systems for drinking water, a whole house system that pairs carbon with additional media for the rest of the home, or both together. Not sure which fits your water and your state's numbers? Our PFAS water filter buyer's guide walks the whole decision, and our water specialists can spec a system from a short conversation.
The regulatory picture will keep moving. Comment periods close, rules finalize, states react. Your tap doesn't have to wait for any of it.
Know your number. Then do something about it.
Whatever your state allows, the water in your home is yours to manage.
Frequently Asked Questions About PFAS Limits by State
Which states have their own enforceable PFAS limits in 2026?
Ten states enforce their own PFAS MCLs as of July 2026: New Jersey, New York, New Hampshire, Michigan, Massachusetts, Maine, Rhode Island, Vermont, Pennsylvania, and Wisconsin. Delaware and Illinois enforce the federal limits by writing them into state rules. Everywhere else, the federal rule is the only enforceable PFAS standard, though several states, including California, are working on limits of their own.
Is the federal 4.0 ppt limit for PFOA and PFOS still in effect?
Yes. The 4.0 ppt MCLs for PFOA and PFOS remain in place, and they are not part of EPA's proposed rescission. Public water systems must comply by April 26, 2029, and EPA has proposed letting systems request an extension to April 26, 2031, though that proposal was not final as of July 2026.
What happens to state PFAS limits if EPA finalizes the rescission?
Nothing happens to limits a state wrote itself. New Hampshire, Michigan, Vermont, and Wisconsin regulate the affected compounds individually, New Jersey has its own PFNA MCL, and the Massachusetts, Maine, and Rhode Island sum standards count PFHxS and PFNA inside their 20 ppt totals. The picture differs where a state enforces the federal numbers by adoption, as Delaware and Illinois do: a final rescission would flow through unless the state acts to keep its rules.
If my state has no PFAS limit, does that mean my water is PFAS-free?
No. A missing limit describes your state's rulebook, not your water. PFAS have been detected in water systems across the country, including in states with no state MCL, and the only way to know about your own tap is to test it. The federal PFOA and PFOS limits still apply to your utility either way.
Do private wells have to meet state PFAS limits?
Generally, no. MCLs apply to public water systems, and Michigan, for example, states outright that its drinking water rules do not regulate private residential wells. If you are on a well, testing and treatment are your responsibility, which is also why point-of-use and point-of-entry filtration matter so much for well owners.
What is the PFAS Hazard Index and how does it work?
The Hazard Index is a unitless score for mixtures of PFHxS, PFNA, HFPO-DA (GenX), and PFBS. Each detected compound is divided by its health-based water concentration, the results are added up, and a total above 1 counts as an exceedance. It exists because these compounds often occur together, so regulators evaluate the mixture rather than each one in isolation.
Why is Michigan's PFHxA limit 400,000 ppt when other PFAS limits are single digits?
It is not a typo. Michigan set a separate health-based value for each of its seven regulated PFAS, and those values range from 6 ppt for PFNA up to 400,000 ppt for PFHxA. The spread reflects how differently individual PFAS compounds are evaluated, which is exactly why compound-by-compound limits exist.
What kind of home water filter reduces PFAS?
Three technologies carry the load: activated carbon, which adsorbs PFAS onto its surface; ion exchange resin, which attracts and holds PFAS molecules; and reverse osmosis, which rejects them at a semipermeable membrane. When comparing systems, look for designs built and tested to NSF/ANSI 53 for PFOA and PFOS reduction or NSF/ANSI 58 for reverse osmosis performance.
