Water Quality by County
3,254 counties with public water systems.
| County | State | Systems | Population | Violations |
|---|---|---|---|---|
| Worcester | Maryland | 139 | 95,000 | 2,846 |
| Calhoun | Michigan | 148 | 94,845 | 3,433 |
| Newport | Rhode Island | 47 | 94,584 | 3,746 |
| Henderson | North Carolina | 106 | 94,309 | 6,924 |
| Miami | Ohio | 57 | 94,299 | 4,277 |
| Northumberland | Pennsylvania | 66 | 93,484 | 9,157 |
| Douglas | Oregon | 102 | 93,351 | 10,608 |
| Dubuque | Iowa | 75 | 92,945 | 5,981 |
| Ontario | New York | 53 | 92,863 | 3,446 |
| Bowie | Texas | 21 | 92,734 | 4,152 |
| Eau Claire | Wisconsin | 111 | 92,606 | 2,862 |
| Burleigh | North Dakota | 12 | 92,574 | 263 |
| Penobscot | Maine | 168 | 92,443 | 15,780 |
| Clallam | Washington | 101 | 91,937 | 6,174 |
| Madison | Kentucky | 6 | 91,879 | 1,012 |
| St. Clair | Alabama | 17 | 91,862 | 571 |
| Ozaukee | Wisconsin | 252 | 91,746 | 13,722 |
| Hunterdon | New Jersey | 291 | 91,514 | 16,859 |
| Matanuska-Susitna Borough | Alaska | 345 | 91,419 | 20,535 |
| Glynn | Georgia | 63 | 90,859 | 1,886 |
| Allen | Ohio | 41 | 90,674 | 3,083 |
| Yamhill | Oregon | 91 | 90,673 | 5,862 |
| Jefferson | Wisconsin | 194 | 90,591 | 2,740 |
| Rockdale | Georgia | 5 | 90,172 | 381 |
| Talladega | Alabama | 16 | 90,063 | 1,068 |
| Summit | Colorado | 42 | 89,593 | 4,364 |
| Forrest | Mississippi | 16 | 89,526 | 9,982 |
| Christian | Kentucky | 4 | 89,360 | 404 |
| Jackson | Georgia | 13 | 89,346 | 718 |
| Lycoming | Pennsylvania | 135 | 89,254 | 31,610 |
| Lewis | Washington | 166 | 88,839 | 15,450 |
| Anderson | Texas | 29 | 88,313 | 1,221 |
| Walton | Georgia | 12 | 88,082 | 431 |
| Sutter | California | 35 | 87,991 | 858 |
| Payne | Oklahoma | 22 | 87,559 | 2,865 |
| Vigo | Indiana | 29 | 87,540 | 2,997 |
| Sevier | Tennessee | 51 | 87,523 | 1,240 |
| Ashtabula | Ohio | 57 | 87,422 | 3,578 |
| Saline | Arkansas | 14 | 86,989 | 550 |
| Walker | Alabama | 15 | 86,841 | 540 |
| Lee | Mississippi | 25 | 86,838 | 14,984 |
| Wayne | New York | 34 | 86,692 | 2,331 |
| Wood | West Virginia | 10 | 86,630 | 1,340 |
| Fond du Lac | Wisconsin | 211 | 86,612 | 5,061 |
| Caguas Municipio | Puerto Rico | 23 | 86,609 | 5,193 |
| Hendricks | Indiana | 53 | 85,793 | 3,666 |
| Pike | Pennsylvania | 230 | 85,597 | 31,013 |
| Pottawattamie | Iowa | 33 | 85,108 | 2,294 |
| Hamblen | Tennessee | 5 | 85,076 | 253 |
| Wayne | Ohio | 177 | 85,031 | 10,471 |
| Nacogdoches | Texas | 16 | 84,872 | 1,871 |
| Sumter | South Carolina | 24 | 84,388 | 1,103 |
| Kendall | Illinois | 64 | 84,307 | 6,782 |
| Colbert | Alabama | 13 | 84,199 | 754 |
| Barrow | Georgia | 8 | 84,138 | 514 |
| Victoria | Texas | 49 | 83,831 | 8,645 |
| Calvert | Maryland | 226 | 83,754 | 3,228 |
| Mendocino | California | 147 | 83,647 | 1,646 |
| Naguabo Municipio | Puerto Rico | 5 | 83,376 | 2,551 |
| Bannock | Idaho | 49 | 83,349 | 2,778 |
| Grays Harbor | Washington | 88 | 83,246 | 13,309 |
| Scioto | Ohio | 17 | 83,235 | 348 |
| Greene | Tennessee | 8 | 83,050 | 720 |
| Monongalia | West Virginia | 12 | 82,877 | 1,384 |
| Leavenworth | Kansas | 16 | 82,837 | 1,071 |
| Tuolumne | California | 120 | 82,529 | 1,665 |
| Adams | Pennsylvania | 165 | 82,224 | 14,938 |
| DeKalb | Alabama | 6 | 82,045 | 700 |
| Bulloch | Georgia | 135 | 81,546 | 4,568 |
| San Benito | California | 63 | 81,517 | 1,506 |
| Lenawee | Michigan | 193 | 81,303 | 4,463 |
| Nash | North Carolina | 54 | 81,242 | 11,276 |
| Warren | New York | 231 | 81,131 | 21,880 |
| St. Lawrence | New York | 227 | 81,119 | 16,172 |
| Natrona | Wyoming | 48 | 80,738 | 2,056 |
| Carroll | New Hampshire | 363 | 80,560 | 21,120 |
| Erie | Ohio | 13 | 80,465 | 980 |
| Lauderdale | Mississippi | 14 | 79,977 | 6,664 |
| Kennebec | Maine | 169 | 79,399 | 9,772 |
| Crow Wing | Minnesota | 385 | 79,377 | 2,014 |
| Orange | Texas | 48 | 79,285 | 7,379 |
| Kauai | Hawaii | 19 | 79,166 | 415 |
| Teton | Wyoming | 116 | 78,802 | 5,306 |
| Mason | Washington | 241 | 78,167 | 10,829 |
| Medina | Texas | 33 | 77,946 | 1,742 |
| St. Martin Parish | Louisiana | 25 | 77,708 | 1,995 |
| White | Arkansas | 20 | 77,352 | 937 |
| Dickson | Tennessee | 3 | 77,294 | 205 |
| Bartholomew | Indiana | 15 | 76,992 | 1,592 |
| Liberty | Georgia | 56 | 76,593 | 3,346 |
| Twin Falls | Idaho | 54 | 76,016 | 2,851 |
| Burke | North Carolina | 51 | 75,954 | 2,095 |
| Iberia Parish | Louisiana | 15 | 75,947 | 690 |
| Lawrence | Pennsylvania | 64 | 75,839 | 6,260 |
| Walla Walla | Washington | 69 | 75,527 | 8,476 |
| Athens | Ohio | 13 | 75,476 | 1,430 |
| Williamson | Illinois | 26 | 75,426 | 1,069 |
| Taney | Missouri | 117 | 75,214 | 8,871 |
| Rogers | Oklahoma | 15 | 75,204 | 2,062 |
| Hanover | Virginia | 49 | 75,139 | 2,514 |