US states where PFAS turns up in the most water systems

Key figures

Tested water systems where PFAS was found, by state, 2023 to 2025

Rank 1 has the highest share. A system counts when at least one of its samples had at least one of the 29 PFAS at or above EPA's reporting level. States test different numbers of systems (Texas 1,154, Delaware 36), so a few systems move a small state's share more. The District of Columbia (3 systems tested, PFAS found at all 3) and the territories are not ranked.

Across the United States

• At least one PFAS was found in the drinking water of 3,595 of the 10,312 public water systems tested from 2023 to 2025, 34.9%.
• PFOA or PFOS, the two PFAS with a federal limit of 4 parts per trillion, was found at or above 4 parts per trillion in at least one sample at 1,739 systems, 16.9% of those tested.
• EPA's own comparison of yearly averages with the 2024 limits found 15.5% of large systems (serving more than 10,000 people) above a limit, and estimates 7.8% of all public water systems nationwide.
• Where PFAS was found, it was often more than one: 66% of sampling points with any PFAS had two or more.

What the numbers mean

New Jersey (174 of 265 tested systems) and Connecticut (40 of 63) lead the ranking, with South Carolina, Massachusetts, Texas, Rhode Island and North Carolina all above half.

Found is not the same as unsafe. The reporting levels are 2 to 20 parts per trillion, and most of the chemicals have no federal limit. The sharper test is PFOA and PFOS, which have a limit of 4 parts per trillion as a yearly average: New Jersey 58.5%, Connecticut 55.6%, Massachusetts 41.4%, South Carolina 40.6%, North Carolina 40.2% of tested systems had at least one sample at that level or above. The limit is enforced from 2029 under the 2024 rule, and EPA has proposed giving systems until 2031.