Water Quality by County
3,254 counties with public water systems.
| County | State | Systems | Population | Violations |
|---|---|---|---|---|
| Archer | Texas | 7 | 9,481 | 546 |
| Terry | Texas | 3 | 9,444 | 1,994 |
| Knott | Kentucky | 4 | 9,439 | 703 |
| Chippewa | Minnesota | 20 | 9,402 | 237 |
| Moody | South Dakota | 7 | 9,401 | 920 |
| Delaware | Iowa | 28 | 9,400 | 2,892 |
| Butte | South Dakota | 12 | 9,372 | 1,678 |
| Butler | Iowa | 16 | 9,368 | 987 |
| Walsh | North Dakota | 5 | 9,366 | 110 |
| Chester | Tennessee | 7 | 9,365 | 268 |
| York | Virginia | 13 | 9,358 | 478 |
| County 09015 | 09 | 10 | 9,353 | 3,120 |
| Dooly | Georgia | 7 | 9,350 | 312 |
| Winnebago | Iowa | 19 | 9,330 | 1,587 |
| Stanley | South Dakota | 3 | 9,327 | 44 |
| Broadwater | Montana | 20 | 9,301 | 3,084 |
| County 09027 | 09 | 5 | 9,290 | 557 |
| Carson | Texas | 7 | 9,284 | 422 |
| Washita | Oklahoma | 11 | 9,278 | 1,954 |
| Sussex | Virginia | 12 | 9,275 | 567 |
| Wayne | Missouri | 32 | 9,269 | 1,564 |
| Allendale | South Carolina | 8 | 9,261 | 188 |
| County 06049 | 06 | 10 | 9,219 | 530 |
| Sanders | Montana | 44 | 9,212 | 3,111 |
| Humphreys | Mississippi | 11 | 9,201 | 4,475 |
| Orange | Indiana | 6 | 9,180 | 1,294 |
| Heard | Georgia | 2 | 9,172 | 165 |
| Presque Isle | Michigan | 52 | 9,131 | 1,256 |
| Mason | Illinois | 26 | 9,126 | 710 |
| Bracken | Kentucky | 3 | 9,123 | 169 |
| Grant | South Dakota | 5 | 9,119 | 827 |
| Carbon | Montana | 36 | 9,108 | 5,566 |
| Box Butte | Nebraska | 8 | 9,104 | 243 |
| Brooks | Georgia | 15 | 9,070 | 704 |
| Pope | Minnesota | 55 | 9,055 | 339 |
| Cedar | Missouri | 32 | 9,051 | 2,445 |
| Clinton | Kentucky | 1 | 9,042 | 224 |
| Hamilton | Florida | 17 | 9,009 | 795 |
| Martin | Kentucky | 1 | 9,003 | 402 |
| Keith | Nebraska | 43 | 8,984 | 1,121 |
| Clay | Texas | 10 | 8,983 | 2,087 |
| Washington | Missouri | 39 | 8,949 | 3,278 |
| Lee | Arkansas | 6 | 8,932 | 590 |
| Pike | Arkansas | 9 | 8,923 | 1,058 |
| Jasper | Georgia | 5 | 8,916 | 492 |
| Tucker | West Virginia | 20 | 8,907 | 3,293 |
| Northwest Arctic Borough | Alaska | 16 | 8,887 | 11,683 |
| Winkler | Texas | 12 | 8,887 | 433 |
| Franklin | Mississippi | 14 | 8,883 | 2,777 |
| Evans | Georgia | 13 | 8,880 | 636 |
| Ochiltree | Texas | 4 | 8,852 | 240 |
| Watonwan | Minnesota | 13 | 8,836 | 216 |
| Buffalo | Wisconsin | 70 | 8,821 | 1,285 |
| Kalkaska | Michigan | 80 | 8,807 | 1,976 |
| Wilson | Kansas | 16 | 8,803 | 2,265 |
| County 09012 | 09 | 2 | 8,788 | 266 |
| Worth | Iowa | 14 | 8,762 | 716 |
| Screven | Georgia | 21 | 8,759 | 1,329 |
| Crook | Wyoming | 27 | 8,739 | 675 |
| Hancock | Georgia | 9 | 8,729 | 512 |
| Dent | Missouri | 16 | 8,725 | 661 |
| Union | Pennsylvania | 37 | 8,713 | 5,048 |
| Mills | Iowa | 16 | 8,709 | 1,949 |
| Mitchell | Texas | 6 | 8,682 | 260 |
| Tipton | Indiana | 16 | 8,681 | 1,097 |
| Red Willow | Nebraska | 8 | 8,653 | 518 |
| Ripley | Missouri | 8 | 8,651 | 423 |
| Sevier | Arkansas | 7 | 8,642 | 442 |
| Colfax | Nebraska | 11 | 8,624 | 701 |
| Roseau | Minnesota | 45 | 8,619 | 810 |
| Sullivan | Missouri | 8 | 8,606 | 160 |
| Polk | Tennessee | 19 | 8,603 | 881 |
| Jefferson | Mississippi | 7 | 8,591 | 2,584 |
| McLean | Kentucky | 6 | 8,537 | 784 |
| Metcalfe | Kentucky | 1 | 8,515 | 94 |
| Hampshire | West Virginia | 33 | 8,477 | 5,036 |
| Sac | Iowa | 9 | 8,466 | 464 |
| Lincoln | Georgia | 11 | 8,451 | 237 |
| Latimer | Oklahoma | 6 | 8,443 | 2,178 |
| Berrien | Georgia | 7 | 8,437 | 527 |
| Lee | Kentucky | 1 | 8,428 | 259 |
| Pickett | Tennessee | 1 | 8,428 | 360 |
| Stillwater | Montana | 31 | 8,417 | 5,741 |
| Appling | Georgia | 11 | 8,396 | 184 |
| Hardy | West Virginia | 22 | 8,383 | 2,199 |
| Cook | Minnesota | 101 | 8,374 | 2,529 |
| Wadena | Minnesota | 44 | 8,363 | 319 |
| Roane | West Virginia | 6 | 8,350 | 1,769 |
| Tensas Parish | Louisiana | 5 | 8,336 | 1,589 |
| Dawes | Nebraska | 16 | 8,335 | 917 |
| Bamberg | South Carolina | 8 | 8,335 | 193 |
| Long | Georgia | 56 | 8,332 | 2,895 |
| Mitchell | North Carolina | 25 | 8,317 | 1,602 |
| Carroll | Missouri | 7 | 8,309 | 178 |
| Schuyler | Illinois | 8 | 8,290 | 398 |
| Howard | Missouri | 6 | 8,282 | 371 |
| Fulton | Pennsylvania | 34 | 8,255 | 6,483 |
| Wright | Missouri | 11 | 8,252 | 916 |
| Lawrence | Kentucky | 1 | 8,236 | 121 |
| Grundy | Iowa | 8 | 8,205 | 332 |