Water Quality by County
3,254 counties with public water systems.
| County | State | Systems | Population | Violations |
|---|---|---|---|---|
| Jackson | Texas | 21 | 15,357 | 2,252 |
| Linn | Missouri | 9 | 15,355 | 455 |
| Poweshiek | Iowa | 8 | 15,352 | 310 |
| Nelson | Virginia | 37 | 15,320 | 1,913 |
| Howard | Arkansas | 8 | 15,273 | 656 |
| Beadle | South Dakota | 7 | 15,273 | 1,603 |
| Ray | Missouri | 8 | 15,271 | 270 |
| Dickinson | Kansas | 15 | 15,256 | 1,250 |
| Humboldt | Nevada | 28 | 15,249 | 3,240 |
| Yalobusha | Mississippi | 19 | 15,240 | 6,282 |
| Montour | Pennsylvania | 21 | 15,213 | 2,480 |
| Estill | Kentucky | 2 | 15,150 | 201 |
| Clarke | Mississippi | 12 | 15,146 | 4,862 |
| Dodge | Minnesota | 28 | 15,145 | 245 |
| Minidoka | Idaho | 28 | 15,130 | 2,351 |
| Stone | Mississippi | 11 | 15,116 | 3,664 |
| Page | Iowa | 9 | 15,089 | 1,266 |
| Mitchell | Georgia | 13 | 15,080 | 531 |
| Palo Alto | Iowa | 8 | 15,053 | 391 |
| Barbour | West Virginia | 9 | 15,049 | 482 |
| Saline | Nebraska | 17 | 15,025 | 397 |
| Perquimans | North Carolina | 4 | 15,011 | 303 |
| Hill | Montana | 16 | 14,962 | 2,905 |
| Jackson | Kentucky | 2 | 14,960 | 556 |
| Valdez-Cordova Census Area | Alaska | 53 | 14,940 | 11,666 |
| Trinity | California | 45 | 14,934 | 601 |
| Las Animas | Colorado | 18 | 14,881 | 1,791 |
| McDowell | West Virginia | 23 | 14,881 | 9,042 |
| Fremont | Idaho | 91 | 14,857 | 6,494 |
| Drew | Arkansas | 12 | 14,856 | 393 |
| Green Lake | Wisconsin | 71 | 14,854 | 1,172 |
| Coosa | Alabama | 6 | 14,841 | 454 |
| Pecos | Texas | 10 | 14,839 | 675 |
| Casey | Kentucky | 2 | 14,762 | 1,076 |
| Winneshiek | Iowa | 43 | 14,747 | 3,380 |
| Fayette | Iowa | 24 | 14,722 | 2,125 |
| Parke | Indiana | 33 | 14,721 | 5,088 |
| Waseca | Minnesota | 28 | 14,665 | 160 |
| Hamilton | New York | 88 | 14,618 | 3,822 |
| Baker | Oregon | 23 | 14,604 | 2,306 |
| Andrews | Texas | 5 | 14,579 | 1,517 |
| Conecuh | Alabama | 7 | 14,532 | 911 |
| West Carroll Parish | Louisiana | 7 | 14,532 | 561 |
| Craighead | Arkansas | 13 | 14,530 | 386 |
| Decatur | Tennessee | 8 | 14,522 | 307 |
| Lincoln | Arkansas | 5 | 14,507 | 230 |
| Harrison | Ohio | 30 | 14,503 | 2,320 |
| Otoe | Nebraska | 12 | 14,499 | 441 |
| County 09025 | 09 | 9 | 14,489 | 1,501 |
| Levy | Florida | 67 | 14,454 | 2,644 |
| Martin | Indiana | 5 | 14,412 | 410 |
| Madison | Montana | 45 | 14,392 | 4,771 |
| Massac | Illinois | 6 | 14,370 | 404 |
| Warren | North Carolina | 18 | 14,365 | 1,850 |
| Waushara | Wisconsin | 196 | 14,337 | 3,066 |
| Montague | Texas | 16 | 14,329 | 1,858 |
| Converse | Wyoming | 19 | 14,323 | 520 |
| Perry | Tennessee | 2 | 14,320 | 91 |
| Florida Municipio | Puerto Rico | 1 | 14,303 | 264 |
| Fleming | Kentucky | 3 | 14,301 | 138 |
| Houston | Minnesota | 46 | 14,297 | 611 |
| Gogebic | Michigan | 45 | 14,289 | 814 |
| Dickinson | Iowa | 14 | 14,274 | 722 |
| Cottonwood | Minnesota | 11 | 14,269 | 158 |
| Perry | Missouri | 15 | 14,252 | 1,152 |
| Tattnall | Georgia | 18 | 14,216 | 905 |
| Alleghany | Virginia | 17 | 14,203 | 514 |
| Abbeville | South Carolina | 14 | 14,202 | 1,116 |
| County AK230 | Alaska | 13 | 14,199 | 3,732 |
| Yell | Arkansas | 7 | 14,184 | 868 |
| Rains | Texas | 6 | 14,115 | 1,423 |
| Cedar | Iowa | 28 | 14,112 | 1,926 |
| Kodiak Island Borough | Alaska | 15 | 14,105 | 10,789 |
| Meriwether | Georgia | 11 | 14,104 | 987 |
| Union | South Dakota | 8 | 14,087 | 604 |
| Caldwell | Kentucky | 3 | 14,047 | 402 |
| Jefferson Davis | Mississippi | 8 | 14,040 | 2,764 |
| Clark | Wisconsin | 95 | 14,027 | 2,458 |
| Switzerland | Indiana | 6 | 14,016 | 754 |
| Washington | Georgia | 12 | 13,985 | 565 |
| White | Illinois | 11 | 13,966 | 388 |
| McDonald | Missouri | 27 | 13,946 | 3,387 |
| Sequatchie | Tennessee | 5 | 13,944 | 95 |
| Callahan | Texas | 5 | 13,911 | 1,049 |
| Rio Grande | Colorado | 50 | 13,852 | 5,311 |
| Juniata | Pennsylvania | 37 | 13,839 | 8,800 |
| Juab | Utah | 15 | 13,808 | 2,949 |
| Ste. Genevieve | Missouri | 17 | 13,798 | 851 |
| Larue | Kentucky | 2 | 13,691 | 200 |
| Montgomery | Mississippi | 17 | 13,687 | 4,888 |
| Hamilton | Iowa | 12 | 13,679 | 535 |
| Morrow | Oregon | 15 | 13,645 | 2,014 |
| Carroll | Illinois | 41 | 13,629 | 2,138 |
| Emery | Utah | 20 | 13,626 | 2,451 |
| County 09021 | 09 | 8 | 13,612 | 500 |
| Morgan | Missouri | 76 | 13,601 | 5,617 |
| Lawrence | Illinois | 15 | 13,590 | 577 |
| Benton | Missouri | 86 | 13,578 | 9,523 |
| Jackson | Arkansas | 11 | 13,566 | 628 |
| Madison Parish | Louisiana | 4 | 13,542 | 548 |