Water Quality by County
3,254 counties with public water systems.
| County | State | Systems | Population | Violations |
|---|---|---|---|---|
| San Miguel | New Mexico | 45 | 24,231 | 6,436 |
| Calumet | Wisconsin | 49 | 24,228 | 1,547 |
| Iosco | Michigan | 85 | 24,210 | 698 |
| Franklin | Kansas | 14 | 24,169 | 1,252 |
| Mahaska | Iowa | 4 | 24,159 | 390 |
| Simpson | Kentucky | 2 | 24,096 | 357 |
| Clay | Mississippi | 8 | 24,061 | 3,251 |
| Custer | Oklahoma | 12 | 24,061 | 2,285 |
| Jackson | West Virginia | 10 | 24,044 | 1,614 |
| Shawano | Wisconsin | 115 | 24,019 | 2,743 |
| Lamoille | Vermont | 69 | 24,007 | 7,946 |
| Harrison | Kentucky | 2 | 23,999 | 813 |
| Fentress | Tennessee | 3 | 23,981 | 271 |
| Marion | Kentucky | 2 | 23,953 | 147 |
| Marshall | Mississippi | 13 | 23,916 | 3,101 |
| Sumner | Kansas | 19 | 23,906 | 2,443 |
| Newton | Missouri | 42 | 23,863 | 3,651 |
| Anson | North Carolina | 8 | 23,837 | 1,735 |
| Blaine | Idaho | 46 | 23,812 | 2,888 |
| Geneva | Alabama | 9 | 23,793 | 648 |
| Cass | Texas | 15 | 23,724 | 4,026 |
| Teller | Colorado | 51 | 23,723 | 9,700 |
| Effingham | Illinois | 16 | 23,718 | 682 |
| Gonzales | Texas | 7 | 23,700 | 799 |
| Putnam | Georgia | 26 | 23,663 | 1,083 |
| Seward | Kansas | 9 | 23,643 | 325 |
| Edmunds | South Dakota | 8 | 23,620 | 157 |
| Washington | Indiana | 7 | 23,603 | 990 |
| Donley | Texas | 8 | 23,584 | 375 |
| Garvin | Oklahoma | 13 | 23,570 | 2,955 |
| Caledonia | Vermont | 64 | 23,503 | 9,284 |
| Jones | Georgia | 8 | 23,496 | 252 |
| Snyder | Pennsylvania | 49 | 23,485 | 11,347 |
| Stoddard | Missouri | 20 | 23,436 | 879 |
| Columbia | Arkansas | 15 | 23,425 | 1,012 |
| Dakota | Nebraska | 10 | 23,417 | 243 |
| Gulf | Florida | 11 | 23,396 | 372 |
| Newberry | South Carolina | 13 | 23,393 | 562 |
| Dickinson | Michigan | 34 | 23,369 | 1,196 |
| Henry | Missouri | 13 | 23,361 | 728 |
| Itawamba | Mississippi | 9 | 23,348 | 1,872 |
| Peach | Georgia | 6 | 23,279 | 385 |
| Antrim | Michigan | 114 | 23,273 | 1,797 |
| Adams | Wisconsin | 200 | 23,263 | 2,152 |
| Allen | Kentucky | 2 | 23,262 | 450 |
| Smith | Tennessee | 7 | 23,207 | 307 |
| Pottawatomie | Kansas | 19 | 23,206 | 1,299 |
| Anderson | Kentucky | 2 | 23,165 | 468 |
| Apache | Arizona | 47 | 23,153 | 5,592 |
| Klickitat | Washington | 55 | 23,094 | 2,241 |
| Henry | Alabama | 7 | 23,076 | 1,004 |
| Marion | Mississippi | 11 | 23,060 | 5,168 |
| Brown | Minnesota | 32 | 23,015 | 187 |
| Adams | Indiana | 74 | 22,969 | 4,249 |
| Cherokee | Alabama | 4 | 22,968 | 161 |
| Sevier | Utah | 34 | 22,920 | 4,309 |
| Fairfield | South Carolina | 18 | 22,911 | 666 |
| Carbon | Utah | 21 | 22,864 | 1,737 |
| St. James Parish | Louisiana | 5 | 22,854 | 731 |
| Caddo | Oklahoma | 32 | 22,848 | 7,066 |
| Leon | Texas | 18 | 22,828 | 1,221 |
| Summers | West Virginia | 17 | 22,827 | 4,549 |
| Barton | Kansas | 16 | 22,818 | 1,473 |
| Franklin | Virginia | 74 | 22,763 | 3,776 |
| White | Georgia | 40 | 22,688 | 927 |
| Franklin | Maine | 61 | 22,669 | 3,907 |
| Polk | Wisconsin | 186 | 22,665 | 3,207 |
| Trinity | Texas | 22 | 22,584 | 3,664 |
| Gilpin | Colorado | 21 | 22,561 | 989 |
| Malheur | Oregon | 25 | 22,466 | 4,518 |
| Pittsylvania | Virginia | 56 | 22,460 | 2,695 |
| Leake | Mississippi | 13 | 22,457 | 7,175 |
| Duchesne | Utah | 31 | 22,426 | 3,779 |
| Meade | South Dakota | 56 | 22,391 | 3,218 |
| Henry | Kentucky | 3 | 22,370 | 414 |
| Decatur | Indiana | 17 | 22,369 | 2,094 |
| Clay | Arkansas | 13 | 22,353 | 615 |
| Spencer | Kentucky | 1 | 22,286 | 46 |
| Hart | Kentucky | 3 | 22,284 | 211 |
| Attala | Mississippi | 14 | 22,247 | 5,615 |
| Mineral | West Virginia | 16 | 22,240 | 9,391 |
| Washington | Maine | 108 | 22,237 | 7,972 |
| Colleton | South Carolina | 38 | 22,221 | 520 |
| Grand | Utah | 21 | 22,221 | 3,250 |
| Upshur | West Virginia | 8 | 22,120 | 698 |
| Adair | Kentucky | 1 | 22,113 | 55 |
| Jersey | Illinois | 7 | 22,083 | 303 |
| San Miguel | Colorado | 20 | 22,019 | 4,325 |
| Stutsman | North Dakota | 9 | 22,008 | 328 |
| Goochland | Virginia | 38 | 21,841 | 1,424 |
| Juana Diaz Municipio | Puerto Rico | 11 | 21,739 | 3,165 |
| Breckinridge | Kentucky | 3 | 21,624 | 525 |
| Tyler | Texas | 19 | 21,622 | 3,562 |
| Lincoln | Kentucky | 4 | 21,615 | 508 |
| Young | Texas | 6 | 21,578 | 363 |
| Marlboro | South Carolina | 8 | 21,574 | 255 |
| Clinton | Ohio | 6 | 21,539 | 834 |
| Otsego | Michigan | 126 | 21,534 | 2,311 |
| Upson | Georgia | 16 | 21,527 | 833 |
| Dawson | Nebraska | 37 | 21,525 | 823 |