Tap water quality by state
Community water systems ranked by how often they exceed the EPA lead action level, with PFAS detection alongside. Official EPA monitoring data.
Lead — share of community water systems whose LCR 90th-percentile
result exceeds the EPA action level of 0.015 mg/L.
PFAS — share of systems where PFOA or PFOS was detected in
UCMR-5 (2023–2025). The 2024 federal limit for each is 0.004 µg/L.
States with fewer than 20 tested systems are listed but not ranked — a rate
off a handful of systems is not meaningful.
| Rank | State | Lead exceedance | PFAS detection | Systems |
|---|---|---|---|---|
| 1 | New Hampshire | 77.1% | 31.3% | 681 |
| 2 | Pennsylvania | 24% | 30% | 1,782 |
| 3 | PR | 7.9% | 25% | 381 |
| 4 | Rhode Island | 6.8% | 40% | 92 |
| 5 | Arkansas | 5.6% | 0.6% | 660 |
| 6 | MP | 5.6% | 100% | 36 |
| 7 | Michigan | 4% | 2.9% | 1,429 |
| 8 | New Mexico | 2.6% | 5.2% | 592 |
| 9 | Vermont | 2.2% | 2.9% | 376 |
| 10 | Massachusetts | 2% | 41.2% | 563 |
| 11 | Maryland | 1.9% | 19.2% | 451 |
| 12 | Oregon | 1.9% | 8.1% | 943 |
| 13 | Utah | 1.7% | 3.1% | 551 |
| 14 | Indiana | 1.5% | 9.6% | 712 |
| 15 | Connecticut | 1.4% | 58.7% | 505 |
| 16 | North Carolina | 1.3% | 39.9% | 1,958 |
| 17 | North Dakota | 1.3% | 0% | 318 |
| 18 | New Jersey | 1.3% | 61% | 618 |
| 19 | New York | 1.3% | 15.2% | 2,203 |
| 20 | South Carolina | 1.3% | 40.2% | 558 |
| 21 | Arizona | 1.1% | 14.9% | 908 |
| 22 | Illinois | 1.1% | 5.1% | 1,752 |
| 23 | Mississippi | 1.1% | 3.1% | 947 |
| 24 | Nebraska | 1% | 7.8% | 593 |
| 25 | Washington | 1% | 13.9% | 2,404 |
| 26 | Wisconsin | 1% | 1.9% | 831 |
| 27 | California | 0.9% | 23.6% | 3,059 |
| 28 | Maine | 0.9% | 13.2% | 348 |
| 29 | Nevada | 0.9% | 10.8% | 230 |
| 30 | Oklahoma | 0.9% | 8.1% | 866 |
| 31 | West Virginia | 0.9% | — | 357 |
| 32 | Delaware | 0.8% | 40.9% | 135 |
| 33 | Idaho | 0.8% | 4.8% | 773 |
| 34 | Montana | 0.8% | 5% | 818 |
| 35 | Alabama | 0.7% | 25.8% | 546 |
| 36 | Georgia | 0.7% | 17.6% | 1,722 |
| 37 | Alaska | 0.5% | 14.3% | 406 |
| 38 | Texas | 0.5% | 9.4% | 4,615 |
| 39 | Virginia | 0.5% | 12.3% | 849 |
| 40 | Minnesota | 0.4% | 8.1% | 998 |
| 41 | Missouri | 0.4% | 4.6% | 1,688 |
| 42 | Colorado | 0.3% | 9.5% | 1,108 |
| 43 | Florida | 0.3% | 39.6% | 1,513 |
| 44 | Iowa | 0.3% | 4.6% | 1,078 |
| 45 | Ohio | 0.3% | 17.7% | 1,048 |
| 46 | Wyoming | 0.3% | 100% | 317 |
| 47 | Kansas | 0.1% | 5% | 846 |
| 48 | Louisiana | 0.1% | 2.7% | 815 |
| 49 | Hawaii | 0% | 0% | 116 |
| 50 | Kentucky | 0% | 13.4% | 375 |
| 51 | South Dakota | 0% | 1.8% | 513 |
| 52 | Tennessee | 0% | 13.6% | 450 |