Water Quality by County
3,254 counties with public water systems.
| County | State | Systems | Population | Violations |
|---|---|---|---|---|
| Linn | Iowa | 83 | 224,711 | 8,540 |
| Niagara | New York | 21 | 223,670 | 128 |
| Yavapai | Arizona | 238 | 223,192 | 25,793 |
| Kanawha | West Virginia | 4 | 223,150 | 2,563 |
| Forsyth | Georgia | 8 | 222,696 | 347 |
| St. Johns | Florida | 56 | 221,945 | 1,953 |
| Union | North Carolina | 42 | 221,518 | 3,657 |
| Santa Rosa | Florida | 23 | 221,076 | 463 |
| St. Joseph | Indiana | 221 | 218,797 | 16,354 |
| Henry | Georgia | 8 | 218,714 | 444 |
| Cumberland | Maine | 224 | 217,874 | 17,731 |
| Yuma | Arizona | 51 | 217,720 | 16,217 |
| Harford | Maryland | 238 | 217,578 | 3,670 |
| Cleveland | Oklahoma | 73 | 216,341 | 8,560 |
| Calcasieu Parish | Louisiana | 80 | 216,042 | 3,535 |
| Clay | Florida | 79 | 215,697 | 1,593 |
| Frederick | Maryland | 220 | 215,362 | 3,555 |
| Canyon | Idaho | 143 | 214,619 | 9,692 |
| Richmond | Georgia | 8 | 213,307 | 601 |
| Kaufman | Texas | 31 | 212,736 | 1,389 |
| Davidson | North Carolina | 8 | 212,093 | 871 |
| Shasta | California | 180 | 211,056 | 2,130 |
| Shelby | Alabama | 16 | 210,543 | 749 |
| Wilson | Tennessee | 7 | 209,545 | 225 |
| Champaign | Illinois | 81 | 209,446 | 2,997 |
| New London | Connecticut | 396 | 209,068 | 34,737 |
| Bay | Florida | 36 | 208,775 | 660 |
| Guadalupe | Texas | 18 | 207,597 | 3,891 |
| Potter | Texas | 17 | 207,401 | 1,380 |
| Anderson | South Carolina | 40 | 206,616 | 1,334 |
| Buncombe | North Carolina | 106 | 205,247 | 10,869 |
| Deschutes | Oregon | 138 | 204,759 | 5,986 |
| Johnston | North Carolina | 54 | 204,441 | 7,155 |
| Oneida | New York | 127 | 204,352 | 10,444 |
| Beaufort | South Carolina | 45 | 203,764 | 537 |
| York | South Carolina | 137 | 202,935 | 8,274 |
| Sussex | New Jersey | 479 | 202,616 | 27,540 |
| DeSoto | Mississippi | 23 | 202,603 | 5,185 |
| Kenton | Kentucky | 1 | 199,460 | 674 |
| Saratoga | New York | 218 | 198,697 | 23,775 |
| Gaston | North Carolina | 255 | 198,602 | 26,256 |
| Jackson | Oregon | 208 | 197,238 | 12,362 |
| Vanderburgh | Indiana | 6 | 195,582 | 332 |
| Delaware | Ohio | 5 | 195,368 | 521 |
| Harrison | Mississippi | 52 | 193,791 | 15,513 |
| Sullivan | Tennessee | 18 | 193,299 | 1,254 |
| Washington | Rhode Island | 188 | 192,066 | 12,743 |
| Washington | Arkansas | 29 | 189,281 | 647 |
| Monroe | Pennsylvania | 443 | 188,975 | 72,365 |
| Ouachita Parish | Louisiana | 31 | 188,938 | 4,888 |
| Peoria | Illinois | 83 | 188,814 | 7,041 |
| Clermont | Ohio | 9 | 187,400 | 1,204 |
| Clark | Indiana | 11 | 186,708 | 1,313 |
| Imperial | California | 79 | 186,350 | 1,878 |
| Jefferson | Missouri | 99 | 186,057 | 6,751 |
| Rankin | Mississippi | 36 | 185,902 | 24,667 |
| Maury | Tennessee | 4 | 183,859 | 237 |
| Sangamon | Illinois | 68 | 183,628 | 1,245 |
| Centre | Pennsylvania | 78 | 182,614 | 21,783 |
| Broome | New York | 170 | 182,088 | 3,720 |
| Madera | California | 204 | 181,924 | 7,852 |
| Kent | Rhode Island | 42 | 180,873 | 2,880 |
| Coconino | Arizona | 116 | 180,537 | 13,681 |
| Greene | Ohio | 56 | 180,062 | 3,157 |
| Outagamie | Wisconsin | 107 | 179,535 | 1,999 |
| Racine | Wisconsin | 195 | 179,476 | 10,597 |
| Beaver | Pennsylvania | 96 | 179,116 | 14,356 |
| St. Louis | Minnesota | 364 | 178,965 | 3,967 |
| Lee | Alabama | 7 | 178,816 | 572 |
| Kootenai | Idaho | 195 | 178,648 | 7,546 |
| Scott | Iowa | 77 | 178,285 | 5,956 |
| Hernando | Florida | 113 | 178,191 | 3,264 |
| Cass | North Dakota | 27 | 176,764 | 915 |
| Midland | Texas | 71 | 176,748 | 13,936 |
| Lexington | South Carolina | 135 | 176,237 | 6,415 |
| Tippecanoe | Indiana | 88 | 175,836 | 7,057 |
| Lackawanna | Pennsylvania | 119 | 172,971 | 22,460 |
| Pitt | North Carolina | 15 | 172,848 | 1,946 |
| McLean | Illinois | 90 | 171,235 | 10,265 |
| Saginaw | Michigan | 61 | 170,110 | 1,094 |
| Maui | Hawaii | 39 | 169,182 | 2,585 |
| Yellowstone | Montana | 116 | 168,956 | 16,006 |
| Indian River | Florida | 17 | 168,214 | 836 |
| Johnson | Iowa | 125 | 167,742 | 10,912 |
| Pueblo | Colorado | 29 | 167,384 | 4,552 |
| Stearns | Minnesota | 214 | 167,300 | 2,315 |
| Taylor | Texas | 17 | 166,322 | 1,916 |
| Rapides Parish | Louisiana | 24 | 165,953 | 1,472 |
| Sumter | Florida | 82 | 165,596 | 1,728 |
| York | Maine | 190 | 164,445 | 12,163 |
| Rock Island | Illinois | 120 | 164,178 | 6,591 |
| Dorchester | South Carolina | 56 | 164,012 | 369 |
| Blount | Tennessee | 16 | 163,777 | 325 |
| Mesa | Colorado | 37 | 163,215 | 2,022 |
| Mayaguez Municipio | Puerto Rico | 3 | 162,876 | 1,429 |
| Berkeley | South Carolina | 63 | 162,162 | 576 |
| Napa | California | 185 | 161,964 | 2,698 |
| Martin | Florida | 60 | 161,250 | 3,412 |
| Black Hawk | Iowa | 19 | 161,225 | 824 |
| Wyandotte | Kansas | 2 | 160,765 | 103 |