Water Quality by County
3,254 counties with public water systems.
| County | State | Systems | Population | Violations |
|---|---|---|---|---|
| Belknap | New Hampshire | 255 | 74,926 | 16,111 |
| Coryell | Texas | 15 | 74,675 | 1,383 |
| Lafayette | Mississippi | 24 | 74,518 | 9,184 |
| Russell | Alabama | 5 | 74,437 | 600 |
| Cole | Missouri | 17 | 73,799 | 1,128 |
| Carteret | North Carolina | 77 | 73,753 | 5,165 |
| Dallas | Iowa | 22 | 73,706 | 1,211 |
| Columbiana | Ohio | 115 | 73,673 | 6,587 |
| Dodge | Wisconsin | 180 | 73,540 | 5,065 |
| Montgomery | Virginia | 28 | 73,521 | 1,549 |
| Rio Grande Municipio | Puerto Rico | 5 | 73,495 | 2,133 |
| Howard | Indiana | 44 | 73,406 | 5,685 |
| Caldwell | North Carolina | 29 | 73,385 | 1,810 |
| Raleigh | West Virginia | 18 | 73,148 | 3,512 |
| Cape Girardeau | Missouri | 30 | 73,133 | 2,275 |
| Harrison | Texas | 34 | 73,072 | 4,093 |
| Cumberland | Tennessee | 7 | 72,854 | 300 |
| Tooele | Utah | 34 | 72,658 | 5,457 |
| Lake | California | 81 | 72,533 | 1,460 |
| Tuscarawas | Ohio | 80 | 72,418 | 3,876 |
| Benton | Oregon | 48 | 72,210 | 3,039 |
| Autauga | Alabama | 7 | 71,634 | 885 |
| Dorado Municipio | Puerto Rico | 2 | 71,613 | 828 |
| Laurel | Kentucky | 5 | 71,586 | 832 |
| Lincoln | North Carolina | 61 | 71,447 | 3,442 |
| Kershaw | South Carolina | 11 | 71,420 | 235 |
| Walker | Texas | 33 | 71,374 | 4,949 |
| Canadian | Oklahoma | 18 | 71,324 | 3,380 |
| Umatilla | Oregon | 76 | 71,259 | 7,500 |
| Franklin | Missouri | 84 | 71,212 | 5,402 |
| Rutland | Vermont | 172 | 71,079 | 26,092 |
| Otero | New Mexico | 55 | 71,033 | 7,026 |
| Muskogee | Oklahoma | 20 | 71,012 | 7,166 |
| Muskingum | Ohio | 23 | 70,931 | 2,167 |
| Georgetown | South Carolina | 24 | 70,899 | 318 |
| Jones | Mississippi | 23 | 70,823 | 13,339 |
| Vermilion Parish | Louisiana | 12 | 70,792 | 645 |
| Roane | Tennessee | 9 | 70,455 | 623 |
| Coffee | Tennessee | 9 | 70,359 | 443 |
| Tipton | Tennessee | 9 | 70,188 | 300 |
| Cecil | Maryland | 197 | 70,068 | 6,007 |
| Androscoggin | Maine | 94 | 70,047 | 4,940 |
| Grand Forks | North Dakota | 9 | 69,787 | 232 |
| Ross | Ohio | 9 | 69,697 | 417 |
| Blount | Alabama | 12 | 69,493 | 803 |
| Oktibbeha | Mississippi | 24 | 69,436 | 10,067 |
| Starr | Texas | 11 | 69,431 | 2,339 |
| Dale | Alabama | 15 | 69,284 | 472 |
| Darlington | South Carolina | 6 | 69,227 | 155 |
| San Patricio | Texas | 20 | 69,107 | 1,536 |
| Cheshire | New Hampshire | 170 | 69,097 | 12,313 |
| Carbon | Pennsylvania | 162 | 69,040 | 20,757 |
| Windsor | Vermont | 165 | 68,991 | 15,601 |
| Allegany | Maryland | 59 | 68,967 | 1,901 |
| Windham | Vermont | 199 | 68,946 | 22,614 |
| Navarro | Texas | 23 | 68,758 | 1,611 |
| Coffee | Alabama | 8 | 68,696 | 991 |
| Somerset | Pennsylvania | 110 | 68,679 | 18,586 |
| Hood | Texas | 65 | 68,561 | 4,550 |
| Sauk | Wisconsin | 199 | 68,432 | 4,499 |
| Eaton | Michigan | 105 | 68,299 | 3,144 |
| Salem | New Jersey | 105 | 68,202 | 5,511 |
| Polk | Texas | 66 | 68,150 | 6,339 |
| Geauga | Ohio | 261 | 67,981 | 20,222 |
| Lewis and Clark | Montana | 162 | 67,948 | 24,270 |
| Adams | Illinois | 25 | 67,920 | 2,040 |
| Catoosa | Georgia | 3 | 67,726 | 113 |
| Creek | Oklahoma | 35 | 67,671 | 9,374 |
| Warren | Tennessee | 3 | 67,603 | 124 |
| Wood | Texas | 23 | 67,540 | 1,238 |
| Eddy | New Mexico | 28 | 67,422 | 3,187 |
| Hancock | Ohio | 41 | 67,164 | 3,194 |
| McCracken | Kentucky | 3 | 67,098 | 399 |
| Midland | Michigan | 34 | 67,083 | 402 |
| Wilson | North Carolina | 26 | 67,070 | 5,266 |
| Lowndes | Mississippi | 14 | 67,039 | 4,212 |
| Lea | New Mexico | 23 | 66,976 | 1,905 |
| Boyd | Kentucky | 3 | 66,399 | 832 |
| Huron | Ohio | 26 | 66,221 | 1,305 |
| Vernon Parish | Louisiana | 20 | 66,152 | 623 |
| Jefferson | Arkansas | 14 | 66,046 | 497 |
| Cattaraugus | New York | 148 | 66,030 | 5,265 |
| Nassau | Florida | 54 | 65,987 | 2,307 |
| Whitman | Washington | 33 | 65,902 | 1,462 |
| Lamar | Mississippi | 11 | 65,838 | 6,121 |
| Harrison | West Virginia | 22 | 65,815 | 4,253 |
| Ward | North Dakota | 14 | 65,645 | 589 |
| Orangeburg | South Carolina | 33 | 65,626 | 530 |
| Tallapoosa | Alabama | 11 | 65,594 | 596 |
| Spalding | Georgia | 6 | 65,298 | 304 |
| Franklin | Kentucky | 4 | 65,214 | 485 |
| Box Elder | Utah | 49 | 65,132 | 9,379 |
| Columbia | Pennsylvania | 94 | 65,107 | 14,926 |
| Loudon | Tennessee | 4 | 65,003 | 186 |
| Pope | Arkansas | 13 | 64,993 | 366 |
| Bedford | Tennessee | 5 | 64,916 | 495 |
| Rice | Minnesota | 71 | 64,806 | 729 |
| Columbia | Wisconsin | 141 | 64,692 | 3,867 |
| Pulaski | Missouri | 24 | 64,569 | 1,348 |
| Manitowoc | Wisconsin | 143 | 64,329 | 2,305 |