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 | 83.3% | 31.3% | 681 |
| 2 | Rhode Island | 34.1% | 40% | 92 |
| 3 | Vermont | 28.8% | 2.9% | 376 |
| 4 | Pennsylvania | 28.2% | 30% | 1,782 |
| 5 | Maine | 23.8% | 13.2% | 348 |
| 6 | Massachusetts | 23.1% | 41.2% | 563 |
| 7 | PR | 20.8% | 25% | 381 |
| 8 | North Carolina | 20.4% | 39.9% | 1,958 |
| 9 | South Carolina | 17.4% | 40.2% | 558 |
| 10 | Alaska | 17.1% | 14.3% | 406 |
| 11 | Delaware | 15.9% | 40.9% | 135 |
| 12 | Michigan | 13.3% | 2.9% | 1,429 |
| 13 | Ohio | 12.8% | 17.7% | 1,048 |
| 14 | California | 12.2% | 23.6% | 3,059 |
| 15 | Hawaii | 11.3% | 0% | 116 |
| 16 | Minnesota | 10.6% | 8.1% | 998 |
| 17 | Oregon | 10.1% | 8.1% | 943 |
| 18 | New Jersey | 9.4% | 61% | 618 |
| 19 | Arizona | 9.1% | 14.9% | 908 |
| 20 | Virginia | 8.8% | 12.3% | 849 |
| 21 | New York | 8.6% | 15.2% | 2,203 |
| 22 | New Mexico | 8% | 5.2% | 592 |
| 23 | Nevada | 7.6% | 10.8% | 230 |
| 24 | Maryland | 7.5% | 19.2% | 451 |
| 25 | Arkansas | 7.4% | 0.6% | 660 |
| 26 | Wisconsin | 7.2% | 1.9% | 831 |
| 27 | Indiana | 6.8% | 9.6% | 712 |
| 28 | Connecticut | 6.6% | 58.7% | 505 |
| 29 | Georgia | 6.4% | 17.6% | 1,722 |
| 30 | Illinois | 6.4% | 5.1% | 1,752 |
| 31 | Idaho | 6% | 4.8% | 773 |
| 32 | Iowa | 5.7% | 4.6% | 1,078 |
| 33 | MP | 5.6% | 100% | 36 |
| 34 | Mississippi | 5.4% | 3.1% | 947 |
| 35 | Tennessee | 5.3% | 13.6% | 450 |
| 36 | Florida | 4.9% | 39.6% | 1,513 |
| 37 | Oklahoma | 4.9% | 8.1% | 866 |
| 38 | Colorado | 4.8% | 9.5% | 1,108 |
| 39 | Wyoming | 4.7% | 100% | 317 |
| 40 | Washington | 4.5% | 13.9% | 2,404 |
| 41 | Utah | 4.1% | 3.1% | 551 |
| 42 | Montana | 3.8% | 5% | 818 |
| 43 | Texas | 3.7% | 9.4% | 4,615 |
| 44 | West Virginia | 3.7% | — | 357 |
| 45 | Louisiana | 3.4% | 2.7% | 815 |
| 46 | Nebraska | 3.4% | 7.8% | 593 |
| 47 | Missouri | 3.3% | 4.6% | 1,688 |
| 48 | North Dakota | 3.2% | 0% | 318 |
| 49 | Kansas | 2.2% | 5% | 846 |
| 50 | Alabama | 2% | 25.8% | 546 |
| 51 | South Dakota | 1.4% | 1.8% | 513 |
| 52 | Kentucky | 1.1% | 13.4% | 375 |