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 on EPA UCMR5 PFAS occurrence data; rates use the UCMR5 tested population only. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error.