Tap by Utility

PFAS

PFAS in tap water by state: share of utilities above 4 ppt

Updated · Written from EPA, NSF, CDC and maker documents, each linked at the end · How we decide what to say

Short answer

This guide ranks states by the share of tested utilities whose average PFOA or PFOS exceeded 4 parts per trillion at any sampling point. The figures are computed from EPA's UCMR 5 data, count utilities rather than people, and are screening results rather than violations.

How to read this table

EPA’s 2024 limit for PFOA and PFOS in public drinking water is 4 parts per trillion each. We compare the average of each sampling point’s UCMR 5 results with that level, using EPA’s documented rounding rule (4.05 ppt or more counts as above 4), and count a utility if its highest sampling-point average is above it. States are ranked by the share of tested utilities that do, among utilities serving 3,300 or more people with a complete PFAS test set.

This is a screening comparison, not a compliance record: a utility’s legal compliance is judged on its own regulatory monitoring, under rules that begin to require compliance in 2029.

What these shares do not tell you

  • People, not utilities. A state with a high share may have many small systems. Each utility counts once regardless of size.
  • Small samples. States with few tested utilities can swing widely. We flag any state with fewer than 20.
  • Where the sampling points are. The results are EPA UCMR 5 samples taken by the utility, not samples from your tap.
  • Other PFAS. The table covers PFOA and PFOS, the two limits that remain in force. Other compounds are on each utility’s page (PFAS explained).

The numbers, computed from EPA's file

Nationally, 1,044 of 8,990 utilities serving 3,300 or more people with a complete PFAS test set (12%) had a PFOA or PFOS average above 4 ppt (EPA rounding rule) at one or more sampling points. 7,428 of them (83%) had no detectable PFOA or PFOS.

Highest shares (states with at least 20 tested utilities): Connecticut 48%, New Jersey 48%, Delaware 34%, South Carolina 33%, Florida 33%.

Lowest shares (same filter): Wyoming 0%, Vermont 0%, Montana 0%, North Dakota 0%, South Dakota 0%.

A share counts utilities, not people: a large city and a small town each count once. Results are EPA UCMR 5 screening data (2023 to 2025), not compliance determinations; computed 2026-10-26. Method: methodology. Download the same file: open data.

All 52 states and territories with tested utilities, highest share first
StateUtilities testedPFOA or PFOS above 4 pptShareNo PFOA or PFOS detected
Connecticut562748%22
New Jersey23111048%89
Delaware321134%19
South Carolina1444733%83
Florida35611633%217
Massachusetts2527429%146
Rhode Island26727%16
Pennsylvania3248326%221
North Carolina2506225%152
New Hampshire43921%28
California60012321%444
Alabama2915419%217
Maryland711318%57
Puerto Rico891517%63
Arizona1312015%109
Georgia2282611%187
Ohio3043211%253
West Virginia84810%68
New York279269%237
Washington216199%186
Alaska2329%19
Nevada3539%31
Wisconsin178158%161
Virginia144128%127
Nebraska4137%37
Tennessee265176%229
Oregon11376%105
Maine3526%30
Minnesota179106%163
Oklahoma14075%128
Idaho5224%49
Kentucky21784%190
Kansas8733%82
Indiana20563%185
Illinois436123%411
Colorado14643%131
Texas1,009263%910
Mississippi19653%189
Missouri20252%194
Michigan28652%278
Utah11822%115
Louisiana24410%237
Arkansas15100%150
Iowa12900%123
New Mexico6200%59
Hawaii4200%42
South Dakota4100%40
North Dakota3200%32
Montana3100%30
Vermont3100%31
Wyoming2800%27
District of Columbia300% *3

* Fewer than 20 utilities tested; read the share with caution. "Above 4 ppt" follows EPA's rounding rule (4.05 ppt or more counts as above 4.0), explained on the methodology page.

Related guides

Sources

Not medical or legal advice. This guide summarizes public documents so you can ask better questions of your utility, your health department or a certified lab. For health concerns, talk to a clinician; for compliance questions, to your state drinking water program. Pages on this site that name products may earn a commission, as disclosed on the affiliate disclosure page.