Water Quality by County
3,254 counties with public water systems.
| County | State | Systems | Population | Violations |
|---|---|---|---|---|
| Bell | Kentucky | 6 | 29,010 | 1,345 |
| Platte | Nebraska | 32 | 28,978 | 1,819 |
| Gallia | Ohio | 3 | 28,959 | 197 |
| Morgan | Colorado | 8 | 28,903 | 1,287 |
| Carter | Kentucky | 4 | 28,789 | 538 |
| Arkansas | Arkansas | 11 | 28,761 | 646 |
| Gibson | Indiana | 12 | 28,749 | 1,200 |
| Transylvania | North Carolina | 115 | 28,726 | 11,769 |
| North Slope Borough | Alaska | 78 | 28,722 | 5,005 |
| Murray | Georgia | 8 | 28,695 | 204 |
| Lampasas | Texas | 4 | 28,676 | 627 |
| Dillon | South Carolina | 6 | 28,656 | 51 |
| Benton | Minnesota | 67 | 28,624 | 421 |
| Monroe | Alabama | 8 | 28,590 | 1,218 |
| Meigs | Ohio | 8 | 28,572 | 498 |
| Crawford | Ohio | 10 | 28,553 | 384 |
| Grayson | Kentucky | 2 | 28,471 | 240 |
| Pike | Ohio | 15 | 28,449 | 2,379 |
| Preble | Ohio | 30 | 28,413 | 2,324 |
| Le Sueur | Minnesota | 50 | 28,355 | 624 |
| Audrain | Missouri | 7 | 28,353 | 332 |
| Randolph | Alabama | 6 | 28,348 | 582 |
| Pettis | Missouri | 30 | 28,325 | 3,784 |
| Columbia | Florida | 69 | 28,257 | 3,146 |
| Gunnison | Colorado | 74 | 28,235 | 4,404 |
| Fulton | Ohio | 24 | 28,208 | 1,582 |
| Green | Wisconsin | 52 | 28,087 | 1,393 |
| Marion | Tennessee | 10 | 28,065 | 842 |
| Tuscola | Michigan | 100 | 28,009 | 2,743 |
| Charlevoix | Michigan | 116 | 27,932 | 1,945 |
| Putnam | Indiana | 26 | 27,916 | 2,925 |
| Chenango | New York | 97 | 27,890 | 4,513 |
| Butler | Alabama | 5 | 27,861 | 205 |
| Jackson | Florida | 62 | 27,833 | 1,394 |
| Sheridan | Wyoming | 21 | 27,820 | 524 |
| Huntington | Indiana | 32 | 27,809 | 2,262 |
| Seneca | New York | 87 | 27,760 | 4,623 |
| Fayette | Tennessee | 16 | 27,755 | 397 |
| Hood River | Oregon | 21 | 27,740 | 1,275 |
| Bedford | Pennsylvania | 104 | 27,724 | 14,895 |
| Delta | Colorado | 42 | 27,718 | 7,243 |
| East Feliciana Parish | Louisiana | 10 | 27,684 | 572 |
| Perry | Ohio | 27 | 27,680 | 2,244 |
| McDowell | North Carolina | 96 | 27,653 | 10,183 |
| Tippah | Mississippi | 12 | 27,618 | 7,671 |
| Yabucoa Municipio | Puerto Rico | 14 | 27,610 | 4,444 |
| Freestone | Texas | 24 | 27,607 | 1,731 |
| Macon | Tennessee | 2 | 27,601 | 931 |
| Logan | Oklahoma | 31 | 27,600 | 7,336 |
| Lauderdale | Tennessee | 6 | 27,583 | 228 |
| Corozal Municipio | Puerto Rico | 11 | 27,532 | 5,161 |
| Wapello | Iowa | 5 | 27,531 | 214 |
| Isle of Wight | Virginia | 38 | 27,529 | 4,657 |
| County NN031 | Navajo Nation | 29 | 27,501 | 3,615 |
| Quebradillas Municipio | Puerto Rico | 1 | 27,458 | 838 |
| Gillespie | Texas | 77 | 27,455 | 3,927 |
| Randall | Texas | 35 | 27,429 | 6,202 |
| Wexford | Michigan | 112 | 27,409 | 3,261 |
| Defiance | Ohio | 25 | 27,382 | 2,077 |
| Shelby | Texas | 21 | 27,379 | 5,659 |
| Harlan | Kentucky | 17 | 27,378 | 3,635 |
| Monroe | Illinois | 17 | 27,356 | 733 |
| Randolph | Missouri | 6 | 27,351 | 314 |
| Pickens | Alabama | 5 | 27,330 | 379 |
| Bibb | Alabama | 5 | 27,303 | 225 |
| Leelanau | Michigan | 138 | 27,226 | 1,976 |
| Cass | Nebraska | 42 | 27,182 | 1,450 |
| Washington | Texas | 20 | 27,164 | 806 |
| Isanti | Minnesota | 71 | 27,156 | 354 |
| Hughes | South Dakota | 6 | 27,114 | 317 |
| Ohio | Kentucky | 6 | 27,106 | 1,476 |
| Sunflower | Mississippi | 14 | 27,036 | 8,353 |
| Shenandoah | Virginia | 34 | 27,036 | 1,284 |
| Lee | Georgia | 16 | 26,985 | 652 |
| Union | Mississippi | 12 | 26,974 | 8,034 |
| Grant | New Mexico | 27 | 26,969 | 2,335 |
| Clare | Michigan | 139 | 26,948 | 3,531 |
| Jasper | Mississippi | 16 | 26,909 | 10,451 |
| Becker | Minnesota | 148 | 26,898 | 1,010 |
| Elmore | Idaho | 45 | 26,866 | 3,868 |
| Woodford | Kentucky | 4 | 26,858 | 854 |
| Jefferson | Oregon | 31 | 26,851 | 1,468 |
| Macon | North Carolina | 76 | 26,795 | 7,512 |
| Delta | Michigan | 70 | 26,794 | 3,385 |
| Clear Creek | Colorado | 31 | 26,778 | 2,262 |
| Williams | Ohio | 43 | 26,770 | 2,744 |
| Marinette | Wisconsin | 191 | 26,745 | 5,085 |
| Orleans | Vermont | 74 | 26,684 | 9,369 |
| Bullitt | Kentucky | 2 | 26,626 | 97 |
| DeSoto | Florida | 40 | 26,570 | 798 |
| County 09019 | 09 | 29 | 26,556 | 2,067 |
| Gurabo Municipio | Puerto Rico | 2 | 26,553 | 618 |
| Scott | Indiana | 2 | 26,489 | 1,063 |
| Lawrence | Alabama | 3 | 26,478 | 52 |
| Juneau | Wisconsin | 144 | 26,475 | 2,590 |
| Perry | Pennsylvania | 98 | 26,446 | 16,840 |
| Fremont | Wyoming | 60 | 26,396 | 2,787 |
| Scotland | North Carolina | 18 | 26,384 | 1,984 |
| Mercer | Kentucky | 4 | 26,366 | 967 |
| Grimes | Texas | 29 | 26,364 | 3,078 |