Reference Guide
PFAS Contamination by State: Which States Have the Worst Water Problems (2026)
PFAS has been found in water supplies in all 50 states. The scale of contamination became clearer after the EPA's UCMR 5 (Unregulated Contaminant Monitoring Rule 5) testing, which required large public water systems to test for 29 PFAS compounds between 2021 and 2023. The results confirmed what researchers had suspected: no state is untouched.
Last updated: April 2026 · By the PFASFilterGuide team
The Federal Baseline: EPA's April 2024 MCL Rule
In April 2024, the EPA finalized the first-ever federal Maximum Contaminant Level (MCL) for PFAS in drinking water. The rule sets limits of 4 parts per trillion (ppt) for PFOA and PFOS individually — the two most studied PFAS compounds. It also sets a combined limit of 10 ppt for four additional PFAS (PFNA, PFHxS, HFPO-DA, and PFBS).
Public water systems have until 2029 to comply with these limits. This means millions of Americans are still drinking water that exceeds the new MCL while utilities work toward compliance. Private wells are not covered by the federal rule at all — well owners must test and treat their own water.
Some states have set stricter standards than the EPA rule. A few have no state-level standards and rely entirely on the federal baseline. The table below shows where each state stands as of April 2026.
High Contamination
Major industrial or DoD sources. State or federal enforcement actions underway. Most likely to have documented exceedances.
Medium Contamination
Military base sources dominant. PFAS detected in UCMR 5 testing. Monitoring programs in place; fewer enforcement orders.
Lower Known Contamination
Fewer known industrial or DoD PFAS sources. Lower population density may limit detection data. Not necessarily PFAS-free.
All 50 States: PFAS Contamination Overview
“Known Contaminated Sites” reflects documented PFAS sites in state environmental agency databases and DoD PFAS site tracker data. Actual numbers may be higher as testing programs expand.
| State | Tier | Known Sites | State MCL Status | Key Regulatory Actions | EWG Data |
|---|---|---|---|---|---|
| California | High | 300+ | 5 ppt PFOA / 1 ppt PFOS (state — stricter than EPA) | Mandatory statewide testing; PFAS Response Plan; major DoD and industrial sites | EWG |
| Michigan | High | 250+ | 8 ppt PFOA / 16 ppt PFOS (state — stricter than EPA) | EGLE cleanup orders; PFAS Action Team; Wolverine Worldwide and 3M site remediation | EWG |
| New York | High | 200+ | 10 ppt PFOA and PFOS (state, 2020) | DEC PFAS remediation program; Saint-Gobain sites; Long Island groundwater concerns | EWG |
| Pennsylvania | High | 180+ | Follows EPA 4 ppt federal rule | DEP PFAS Action Plan; multiple DoD cleanup sites; industrial corridor monitoring | EWG |
| Minnesota | High | 180+ | 15 ppt PFOS health-based value; individual MCLs in development | 3M settlement ($850M); East Metro groundwater; MPCA cleanup program | EWG |
| Massachusetts | High | 140+ | 20 ppt for sum of 6 PFAS (MassDEP, 2020) | Saint-Gobain sites; foam training sites; comprehensive testing program | EWG |
| New Jersey | High | 150+ | 14 ppt PFNA; 13 ppt PFOS; 14 ppt PFOA (state, among strictest) | First state with individual PFAS MCLs; mandatory remediation program | EWG |
| North Carolina | High | 120+ | Follows EPA 4 ppt federal rule; GenX designated separately | GenX contamination from Chemours Fayetteville Works; Cape Fear River system | EWG |
| Washington | High | 110+ | No state MCL — Ecology developing PFAS strategy | JBLM McChord AFB; Naval Air Station Whidbey Island; Ecology cleanup orders | EWG |
| Florida | High | 110+ | Follows EPA 4 ppt federal rule | Tyndall AFB; Hurlburt Field; FDEP investigation; firefighting foam site cleanup | EWG |
| Ohio | High | 100+ | Follows EPA 4 ppt federal rule | Multiple DoD sites; OEPA PFAS sampling program | EWG |
| Illinois | High | 95+ | Follows EPA 4 ppt federal rule | IEPA PFAS sampling; Rock Island Arsenal cleanup; Great Lakes Basin concerns | EWG |
| Connecticut | High | 90+ | Follows EPA 4 ppt federal rule; DEEP guidance 70 ppt (pre-2024) | Industrial sites in Naugatuck Valley; DEEP remediation orders | EWG |
| Georgia | High | 75+ | Follows EPA 4 ppt federal rule | Moody AFB; Robins AFB; EPD monitoring program | EWG |
| Texas | High | 80+ | Follows EPA 4 ppt federal rule | TCEQ PFAS sampling; multiple AFB sites; limited mandatory remediation | EWG |
| Colorado | High | 80+ | Follows EPA 4 ppt federal rule; CDPHE developing rule | Peterson SFB; Buckley SFB; Air Force Academy; firefighting foam sites | EWG |
| Alabama | High | 80+ | Follows EPA 4 ppt federal rule | Anniston Superfund site; Decatur 3M plant downstream effects; multiple DoD sites | EWG |
| West Virginia | High | 60+ | Follows EPA 4 ppt federal rule | DuPont/Chemours Washington Works (PFOA source); Parkersburg area contamination; EPA Superfund review | EWG |
| New Hampshire | High | 70+ | 12 ppt PFOA; 15 ppt PFOS; 11 ppt PFNA; 18 ppt PFHxS (strictest combined) | First state with comprehensive individual PFAS MCLs; Saint-Gobain Merrimack plant | EWG |
| Vermont | High | 50+ | 20 ppt for sum of 6 PFAS (DEC, 2020) | Saint-Gobain Bennington plant; Lake Champlain drainage; DEC enforcement and cleanup orders | EWG |
| Virginia | Medium | 85+ | Follows EPA 4 ppt federal rule; DEQ developing PFAS regulation | Langley AFB; Quantico; Fort Belvoir; NSA Hampton Roads; DEQ oversight orders | EWG |
| Maryland | Medium | 65+ | Follows EPA 4 ppt federal rule; MDE PFAS strategy in development | Andrews AFB; Aberdeen Proving Ground; NAS Patuxent River; Chesapeake Bay watershed | EWG |
| Wisconsin | Medium | 65+ | Follows EPA 4 ppt federal rule; DNR PFAS guidance active | Peshtigo area (historical PFAS); Fort McCoy; Fox River Valley industrial sites; DNR enforcement | EWG |
| Maine | Medium | 60+ | 20 ppt for sum of 6 PFAS (DEP, 2022); strictest biosolids rules in US | Statewide biosolids contamination; farmland PFAS; DEP mandatory cleanup orders | EWG |
| Indiana | Medium | 55+ | Follows EPA 4 ppt federal rule | Grissom AFB; industrial sites in northern Indiana; IDEM monitoring program | EWG |
| South Carolina | Medium | 45+ | Follows EPA 4 ppt federal rule | Shaw AFB; Fort Jackson; MCAS Beaufort; DHEC monitoring program | EWG |
| Tennessee | Medium | 40+ | Follows EPA 4 ppt federal rule | Arnold AFB; industrial Tennessee River sites; TDEC sampling in progress | EWG |
| Oregon | Medium | 40+ | Follows EPA 4 ppt federal rule; DEQ PFAS strategy in development | Portland Metro industrial sites; DEQ investigation; Columbia River watershed | EWG |
| Arizona | Medium | 40+ | Follows EPA 4 ppt federal rule | Luke AFB; Davis-Monthan AFB; Fort Huachuca; ADEQ investigation in progress | EWG |
| Missouri | Medium | 40+ | Follows EPA 4 ppt federal rule | Whiteman AFB; Scott AFB; MDNR PFAS sampling; St. Louis area industrial sites | EWG |
| Delaware | Medium | 35+ | Follows EPA 4 ppt federal rule; DNREC plan in development | Dover AFB (significant contamination); industrial corridor; DNREC remediation in progress | EWG |
| Louisiana | Medium | 35+ | Follows EPA 4 ppt federal rule | Barksdale AFB; petrochemical corridor PFAS sources; LDEQ monitoring | EWG |
| Iowa | Medium | 30+ | Follows EPA 4 ppt federal rule | Iowa Air National Guard sites; industrial facilities; IDNR sampling program | EWG |
| Kansas | Medium | 30+ | Follows EPA 4 ppt federal rule | McConnell AFB; Fort Riley; KDHE PFAS investigation in progress | EWG |
| New Mexico | Medium | 30+ | Follows EPA 4 ppt federal rule | Holloman AFB; Cannon AFB; Kirtland AFB; NMED investigation; Albuquerque area groundwater | EWG |
| Rhode Island | Medium | 30+ | Follows EPA 4 ppt federal rule; DEM plan in development | Naval Station Newport; industrial sites; DEM testing program | EWG |
| Kentucky | Medium | 30+ | Follows EPA 4 ppt federal rule | Fort Campbell; Fort Knox; KYDEP sampling; industrial corridor sites | EWG |
| Alaska | Medium | 30+ | Follows EPA 4 ppt federal rule | Elmendorf-Richardson AFB; Eielson AFB; DEC PFAS sampling program | EWG |
| Oklahoma | Medium | 30+ | Follows EPA 4 ppt federal rule | Altus AFB; Tinker AFB; Vance AFB; ODEQ sampling; limited mandatory remediation | EWG |
| Nevada | Medium | 25+ | Follows EPA 4 ppt federal rule; NDEP guidance in development | Nellis AFB; NAS Fallon; NDEP monitoring; Las Vegas valley groundwater concerns | EWG |
| Arkansas | Medium | 25+ | Follows EPA 4 ppt federal rule | Little Rock AFB; industrial sites; ADEQ monitoring started 2023 | EWG |
| Mississippi | Medium | 25+ | Follows EPA 4 ppt federal rule | Columbus AFB; Keesler AFB; MDEQ monitoring started 2023 | EWG |
| Utah | Medium | 25+ | Follows EPA 4 ppt federal rule | Hill AFB (significant foam use); Dugway Proving Ground; DEQ PFAS investigation | EWG |
| Nebraska | Medium | 20+ | Follows EPA 4 ppt federal rule | Offutt AFB (significant foam contamination); NDEE sampling; Missouri River corridor | EWG |
| Hawaii | Medium | 20+ | Follows EPA 4 ppt federal rule | Red Hill fuel facility PFAS concerns; Pearl Harbor NAS; DOH monitoring | EWG |
| Idaho | Medium | 20+ | Follows EPA 4 ppt federal rule | Mountain Home AFB; DEQ PFAS sampling ongoing; limited industrial sources | EWG |
| Montana | Lower | 20+ | Follows EPA 4 ppt federal rule | Malmstrom AFB; limited industrial sources; DEQ monitoring; lower population density limits data | EWG |
| North Dakota | Lower | 10+ | Follows EPA 4 ppt federal rule | Minot AFB; Grand Forks AFB; NDDH monitoring; fewest PFAS sites of Midwest states | EWG |
| South Dakota | Lower | 10+ | Follows EPA 4 ppt federal rule | Ellsworth AFB; DENR monitoring; limited industrial sources; lower population density limits data | EWG |
| Wyoming | Lower | 8+ | Follows EPA 4 ppt federal rule | Warren AFB; DEQ monitoring; limited industrial PFAS sources; one of lowest site counts nationally | EWG |
Sources: EPA UCMR 5 data (2021–2023), DoD PFAS site tracker, state environmental agency databases. Site counts are approximate and grow as testing expands.
Which States Have the Strictest PFAS Laws?
Five states stand out for having adopted MCLs stricter than the 2024 EPA federal rule — often years before the federal government acted.
Vermont
20 ppt for sum of 6 PFAS (2020). Also has the strictest biosolids application rules in the US — PFAS-contaminated biosolids cannot be applied to farmland above 2.5 ppb.
New Hampshire
Individual MCLs for PFOA (12 ppt), PFOS (15 ppt), PFNA (11 ppt), and PFHxS (18 ppt). First state with comprehensive individual compound limits.
Maine
20 ppt for sum of 6 PFAS (2022). First state to ban all non-essential PFAS uses in products. Strictest biosolids regulation nationally.
Massachusetts
20 ppt for sum of 6 PFAS (2020). Active enforcement against utilities exceeding limits, including mandatory alternate water supply orders.
California
5 ppt PFOA and 1 ppt PFOS — the strictest drinking water MCLs in the country. California's PFAS Response Plan covers source water, treatment, and public notification.
New Jersey also deserves mention: it was the first state to adopt individual MCLs for PFNA, PFOS, and PFOA in 2020, predating the EPA federal rule by four years. Its MCLs are set at or near the detection limit for several compounds.
Which States Have the Weakest PFAS Protections?
Most states with no state-level MCLs rely entirely on the 2024 EPA federal rule — which only applies to public water systems serving more than 10,000 people. That leaves private well users with no regulatory protection, regardless of state.
Texas
No state MCL. Limited mandatory remediation despite multiple military PFAS sites. TCEQ monitoring program started later than most states.
Mississippi
No state MCL. Monitoring program started 2023 — among the last states to begin systematic PFAS testing.
Alabama
No state MCL. Significant historical contamination from Anniston-area industrial sources and 3M plant downstream effects. Limited enforcement history.
Wyoming / Montana / North Dakota / South Dakota
No state MCLs. Fewer known industrial sites, but monitoring programs are limited and data is sparse. Military base contamination still present.
Note: The EPA federal rule applies in all states from 2029 forward. States without their own MCLs are not unprotected — they are simply relying on the federal floor rather than setting stricter state standards.
Private Wells: The Gap in Every State
The EPA's PFAS MCL rule covers public water systems. It does not cover the approximately 43 million Americanswho rely on private wells. Well owners in every state are responsible for testing and treating their own water — regardless of how strict their state's PFAS laws are.
If your home is near a military base, industrial facility, or agricultural area that uses PFAS-contaminated biosolids, private well testing is strongly recommended. A PFAS-specific lab panel from Tap Score or SimpleLab costs around $299 and tests for 30+ individual PFAS compounds.
Some states — including Michigan, Vermont, and Maine — have voluntary or targeted private well testing programs for residents near known contamination sites. Check your state environmental agency's website for current offerings.
Recommended: NSF P473 Certified Filters — Regardless of State
Whether you live in California (strictest laws) or Texas (no state MCL), the baseline recommendation is the same: an NSF P473 certified filter for drinking water. Regulatory compliance by your water utility does not mean zero PFAS — it means PFAS below the current limit, which may still be hundreds of times higher than zero.
For drinking water (pitcher / under-sink)
Clearly Filtered is the only widely available pitcher and under-sink system with NSF P473 certification. Removes 99.7% PFOA and 99.9% PFOS.
See our full PFAS filter comparison →For whole-home protection
A whole-house carbon system protects shower water and cooking. Pair with an NSF P473 certified under-sink filter at the kitchen tap.
See whole-house PFAS filter guide →State-Specific PFAS Guides
We have detailed PFAS contamination guides for the following states: