Water Quality by County
3,254 counties with public water systems.
| County | State | Systems | Population | Violations |
|---|---|---|---|---|
| Clay | South Dakota | 4 | 17,173 | 71 |
| Marion | Arkansas | 24 | 17,170 | 1,274 |
| Franklin | Arkansas | 13 | 17,159 | 849 |
| Seminole | Oklahoma | 16 | 17,140 | 5,057 |
| Martin | Minnesota | 22 | 17,101 | 218 |
| Zapata | Texas | 4 | 17,075 | 781 |
| Hart | Georgia | 29 | 17,068 | 565 |
| Avery | North Carolina | 70 | 17,059 | 4,739 |
| Yankton | South Dakota | 9 | 16,948 | 551 |
| Deaf Smith | Texas | 6 | 16,946 | 535 |
| Lewis | New York | 68 | 16,945 | 2,649 |
| Suwannee | Florida | 49 | 16,943 | 2,096 |
| Comerio Municipio | Puerto Rico | 6 | 16,935 | 2,450 |
| Unicoi | Tennessee | 4 | 16,933 | 146 |
| Neosho | Kansas | 15 | 16,913 | 1,635 |
| Butler | Kentucky | 2 | 16,884 | 474 |
| Vernon | Wisconsin | 66 | 16,861 | 2,410 |
| Lincoln | Minnesota | 9 | 16,852 | 93 |
| Russell | Kentucky | 2 | 16,811 | 642 |
| Chester | South Carolina | 19 | 16,800 | 250 |
| Guayanilla Municipio | Puerto Rico | 8 | 16,735 | 2,124 |
| Bath | Kentucky | 3 | 16,722 | 352 |
| Wythe | Virginia | 11 | 16,720 | 436 |
| Skamania | Washington | 58 | 16,716 | 3,052 |
| Jones | Texas | 6 | 16,707 | 1,030 |
| Morgan | Utah | 27 | 16,698 | 3,489 |
| Mineral | Montana | 37 | 16,697 | 1,421 |
| Clay | Kentucky | 2 | 16,681 | 493 |
| Crook | Oregon | 38 | 16,670 | 1,924 |
| Taylor | West Virginia | 5 | 16,650 | 332 |
| Red River | Texas | 8 | 16,591 | 1,274 |
| Newton | Arkansas | 18 | 16,578 | 1,949 |
| Page | Virginia | 37 | 16,574 | 3,967 |
| Atchison | Kansas | 8 | 16,560 | 972 |
| Gloucester | Virginia | 32 | 16,556 | 1,022 |
| Bienville Parish | Louisiana | 22 | 16,537 | 3,875 |
| Bradford | Florida | 24 | 16,504 | 769 |
| Phillips | Arkansas | 9 | 16,499 | 809 |
| Bourbon | Kansas | 6 | 16,490 | 548 |
| Wilcox | Alabama | 6 | 16,464 | 628 |
| Scott | Virginia | 17 | 16,390 | 1,160 |
| Northampton | Virginia | 52 | 16,385 | 3,964 |
| Hockley | Texas | 9 | 16,312 | 4,797 |
| Storey | Nevada | 6 | 16,305 | 1,033 |
| Dade | Georgia | 1 | 16,285 | 24 |
| Union | Kentucky | 4 | 16,273 | 873 |
| Alamosa | Colorado | 17 | 16,272 | 2,084 |
| Caldwell Parish | Louisiana | 11 | 16,257 | 2,154 |
| Dinwiddie | Virginia | 24 | 16,233 | 1,204 |
| Fayette | Indiana | 10 | 16,217 | 596 |
| Saunders | Nebraska | 39 | 16,197 | 1,669 |
| Wayne | Illinois | 12 | 16,194 | 661 |
| Owen | Indiana | 20 | 16,096 | 1,969 |
| Willacy | Texas | 4 | 16,093 | 558 |
| Texas | Missouri | 13 | 16,087 | 869 |
| Lewis | West Virginia | 3 | 16,064 | 277 |
| Pike | Missouri | 6 | 16,049 | 416 |
| Pike | Illinois | 13 | 16,030 | 1,147 |
| George | Mississippi | 10 | 16,008 | 2,640 |
| Jones | Iowa | 36 | 15,999 | 4,745 |
| Todd | Kentucky | 5 | 15,988 | 460 |
| Dickenson | Virginia | 19 | 15,975 | 280 |
| Archuleta | Colorado | 17 | 15,948 | 4,150 |
| Henry | Iowa | 11 | 15,922 | 798 |
| Powell | Kentucky | 4 | 15,917 | 281 |
| Frio | Texas | 7 | 15,824 | 3,458 |
| Cleburne | Alabama | 6 | 15,819 | 248 |
| Ralls | Missouri | 4 | 15,813 | 65 |
| Park | Montana | 58 | 15,803 | 12,317 |
| Churchill | Nevada | 31 | 15,799 | 4,250 |
| County AK130 | Alaska | 28 | 15,797 | 9,191 |
| Elbert | Colorado | 28 | 15,735 | 1,924 |
| Polk | Missouri | 22 | 15,734 | 2,098 |
| Burleson | Texas | 29 | 15,730 | 4,607 |
| Hardeman | Tennessee | 15 | 15,703 | 1,032 |
| Hubbard | Minnesota | 147 | 15,698 | 551 |
| Powhatan | Virginia | 26 | 15,697 | 580 |
| Kane | Utah | 32 | 15,684 | 4,532 |
| Fulton | Arkansas | 15 | 15,663 | 1,085 |
| Person | North Carolina | 46 | 15,657 | 2,804 |
| Shoshone | Idaho | 37 | 15,611 | 1,510 |
| Todd | Minnesota | 73 | 15,609 | 587 |
| Covington | Mississippi | 10 | 15,574 | 4,250 |
| Pendleton | Kentucky | 5 | 15,554 | 517 |
| Crawford | Iowa | 10 | 15,526 | 835 |
| Bourbon | Kentucky | 2 | 15,505 | 996 |
| Hocking | Ohio | 46 | 15,504 | 1,520 |
| Wayne | Georgia | 29 | 15,498 | 976 |
| Wyoming | West Virginia | 20 | 15,488 | 18,999 |
| Clark | Illinois | 9 | 15,476 | 552 |
| Lamar | Alabama | 6 | 15,471 | 181 |
| Carroll | Virginia | 30 | 15,468 | 1,678 |
| New Madrid | Missouri | 15 | 15,452 | 1,160 |
| Richland | North Dakota | 13 | 15,446 | 554 |
| Wyandot | Ohio | 22 | 15,427 | 1,663 |
| Webster | Kentucky | 6 | 15,420 | 999 |
| Ben Hill | Georgia | 2 | 15,414 | 99 |
| Carroll | Ohio | 57 | 15,395 | 2,456 |
| Robertson | Texas | 13 | 15,377 | 626 |
| Mingo | West Virginia | 14 | 15,372 | 5,841 |