PlainWater

National ranking · EPA UCMR5

PFAS in Drinking Water by State

Share of UCMR5-tested systems with at least one PFAS detection. Primary ranking requires ≥10 systems tested so a one-system 100% result cannot lead the list; rates are not SDWIS violation rates (different population - see methodology).

34.4%
National UCMR5 detection rate
10,252
Systems tested (UCMR5)
26.7%
Median rate (≥10 tested)

The verdict

Among states with at least 10 systems tested, New Jersey has the highest PFAS detection rate at 65.2%; the #12 cutoff on the chart above is Ohio at 40.8%, and EPA Region 10 — Tribal Water Systems anchors #57 of the complete eligible list at 0% - against a 34.4% national UCMR5 rate.

65.2%
Detection rate, New Jersey
40.8%
#12 chart cutoff to make this list
0%
#57 · bottom of complete eligible list
34.4%
National UCMR5 detection rate

Highest PFAS detection rates (states with ≥10 systems tested)

Share of UCMR5-tested systems with at least one PFAS detection - not SDWIS violation %

% detected

What this shows New Jersey leads eligible states at 65.2% (median 26.7%).

Source EPA UCMR5 (Fifth Unregulated Contaminant Monitoring Rule) As of UCMR5 2023-2025 cycle

Primary ranking (≥10 systems tested)

Denominator = UCMR5-tested systems only. Floor stated in the lede; #1 carries the small-N caveat even above the floor.

57 states shown

# State Systems Tested PFAS Detected Detection Rate vs median
1 New Jersey(#1 - rate still swings with sample size) 264 172 65.2% +38.5pp
2 Connecticut 63 40 63.5% +36.8pp
3 South Carolina 164 90 54.9% +28.2pp
4 Massachusetts 263 143 54.4% +27.7pp
5 Texas 1,147 610 53.2% +26.5pp
6 Rhode Island 29 15 51.7% +25pp
7 North Carolina 287 143 49.8% +23.1pp
8 Delaware 35 17 48.6% +21.9pp
9 Florida 402 190 47.3% +20.6pp
10 Pennsylvania 389 173 44.5% +17.8pp
11 Minnesota 196 87 44.4% +17.7pp
12 Ohio 346 141 40.8% +14.1pp
13 Puerto Rico 99 38 38.4% +11.7pp
14 Alabama 306 117 38.2% +11.5pp
15 Kentucky 231 87 37.7% +11pp
16 Arizona 152 57 37.5% +10.8pp
17 Oklahoma 166 61 36.7% +10pp
18 Maryland 83 30 36.1% +9.4pp
19 New Hampshire 51 18 35.3% +8.6pp
20 California 694 231 33.3% +6.6pp
21 West Virginia 102 34 33.3% +6.6pp
22 Kansas 103 34 33% +6.3pp
23 Virginia 171 54 31.6% +4.9pp
24 Tennessee 277 87 31.4% +4.7pp
25 Missouri 230 71 30.9% +4.2pp
26 Georgia 254 77 30.3% +3.6pp
27 Alaska 30 9 30% +3.3pp
28 New York 332 98 29.5% +2.8pp
29 Washington 247 66 26.7% +0pp
30 Illinois 487 123 25.3% -1.4pp
31 Wisconsin 202 51 25.2% -1.5pp
32 Maine 41 10 24.4% -2.3pp
33 Indiana 229 55 24% -2.7pp
34 Colorado 163 37 22.7% -4pp
35 Iowa 152 32 21.1% -5.6pp
36 EPA Region 9 — Tribal Water Systems 41 8 19.5% -7.2pp
37 North Dakota 38 7 18.4% -8.3pp
38 Louisiana 265 47 17.7% -9pp
39 Nevada 57 10 17.5% -9.2pp
40 Navajo Nation 13 2 15.4% -11.3pp
41 Oregon 125 18 14.4% -12.3pp
42 South Dakota 49 7 14.3% -12.4pp
43 New Mexico 72 10 13.9% -12.8pp
44 Michigan 318 44 13.8% -12.9pp
45 Idaho 60 8 13.3% -13.4pp
46 Nebraska 53 7 13.2% -13.5pp
47 Utah 129 16 12.4% -14.3pp
48 Montana 45 5 11.1% -15.6pp
49 EPA Region 6 — Tribal Water Systems 18 2 11.1% -15.6pp
50 Wyoming 33 3 9.1% -17.6pp
51 Vermont 37 3 8.1% -18.6pp
52 EPA Region 8 — Tribal Water Systems 13 1 7.7% -19pp
53 EPA Region 5 — Tribal Water Systems 13 1 7.7% -19pp
54 Arkansas 172 10 5.8% -20.9pp
55 Hawaii 45 2 4.4% -22.3pp
56 Mississippi 238 9 3.8% -22.9pp
57 EPA Region 10 — Tribal Water Systems 10 0 0% -26.7pp

Small tested base (<10 systems)

Listed for completeness, not for leadership claims. A 1-of-1 detection reads as 100% without meaning statewide prevalence.

State / territory Systems Tested PFAS Detected Detection Rate
District of Columbia 3 3 100%
American Samoa 1 1 100%
Guam 5 3 60%
Northern Mariana Islands 2 1 50%
EPA Region 1 — Tribal Water Systems 2 1 50%
US Virgin Islands 3 1 33.3%
EPA Region 7 — Tribal Water Systems 1 0 0%
EPA Region 4 — Tribal Water Systems 2 0 0%
EPA Region 2 — Tribal Water Systems 2 0 0%

Download the SDWIS/UCMR5 state landscape snapshot cited on this page: sdwis-state-landscape.csv (same CSV as /statistics, CC0).

Every figure on PlainWater is rendered directly from EPA SDWIS drinking-water data, no number is typed in by an editor. This page draws directly on EPA UCMR5 PFAS occurrence data, no figure is typed in by an editor. Rates use the UCMR5 tested population only. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error.