Water Quality by County
3,254 counties with public water systems.
| County | State | Systems | Population | Violations |
|---|---|---|---|---|
| Chatham | Georgia | 118 | 340,164 | 3,877 |
| Hillsborough | New Hampshire | 280 | 336,342 | 17,880 |
| Genesee | Michigan | 397 | 335,433 | 13,553 |
| Northampton | Pennsylvania | 205 | 334,919 | 15,627 |
| Kitsap | Washington | 221 | 331,366 | 12,667 |
| Henrico | Virginia | 12 | 330,857 | 390 |
| Lorain | Ohio | 17 | 330,150 | 1,534 |
| St. Lucie | Florida | 45 | 330,048 | 3,747 |
| Durham | North Carolina | 50 | 329,624 | 6,257 |
| Osceola | Florida | 64 | 328,370 | 3,645 |
| Anoka | Minnesota | 245 | 328,280 | 2,022 |
| Lane | Oregon | 237 | 327,688 | 16,216 |
| Guam | Guam | 8 | 327,417 | 203 |
| Luzerne | Pennsylvania | 251 | 325,882 | 44,749 |
| Rockland | New York | 49 | 325,504 | 947 |
| Allen | Indiana | 91 | 324,113 | 5,221 |
| Mercer | New Jersey | 97 | 323,840 | 7,431 |
| Lancaster | Nebraska | 89 | 322,833 | 2,037 |
| Waukesha | Wisconsin | 590 | 322,690 | 24,998 |
| Spartanburg | South Carolina | 29 | 318,077 | 154 |
| Lubbock | Texas | 75 | 315,226 | 50,449 |
| Stark | Ohio | 182 | 314,229 | 12,064 |
| St. Charles | Missouri | 54 | 310,776 | 2,706 |
| Howard | Maryland | 88 | 309,588 | 985 |
| Hays | Texas | 124 | 306,942 | 5,506 |
| Anchorage Municipality | Alaska | 156 | 305,331 | 22,461 |
| St. Louis city | Missouri | 1 | 304,709 | 27 |
| Erie | Pennsylvania | 146 | 304,235 | 23,068 |
| Albany | New York | 68 | 303,908 | 5,792 |
| Lafayette Parish | Louisiana | 62 | 303,179 | 2,569 |
| Baldwin | Alabama | 24 | 303,145 | 3,219 |
| Chester | Pennsylvania | 276 | 302,878 | 47,248 |
| Fayette | Kentucky | 1 | 299,501 | 30 |
| Sumner | Tennessee | 6 | 298,975 | 326 |
| Clayton | Georgia | 3 | 298,499 | 272 |
| Weber | Utah | 59 | 297,962 | 9,379 |
| Hinds | Mississippi | 29 | 297,741 | 13,146 |
| Brazos | Texas | 13 | 295,896 | 989 |
| Lehigh | Pennsylvania | 201 | 294,981 | 15,405 |
| El Dorado | California | 129 | 294,812 | 3,192 |
| Gloucester | New Jersey | 181 | 294,691 | 13,479 |
| Dauphin | Pennsylvania | 145 | 294,232 | 21,033 |
| Montgomery | Alabama | 8 | 291,756 | 426 |
| Marion | Florida | 491 | 291,422 | 12,979 |
| Onslow | North Carolina | 20 | 288,498 | 2,366 |
| McLennan | Texas | 58 | 286,609 | 8,955 |
| Kalamazoo | Michigan | 195 | 286,536 | 2,453 |
| Marin | California | 49 | 285,765 | 805 |
| Okaloosa | Florida | 35 | 283,043 | 575 |
| Camden | New Jersey | 102 | 282,373 | 7,095 |
| Smith | Texas | 47 | 281,563 | 4,260 |
| Benton | Washington | 113 | 281,453 | 10,713 |
| Ingham | Michigan | 109 | 279,137 | 3,710 |
| Santa Cruz | California | 96 | 274,174 | 2,563 |
| Webb | Texas | 15 | 273,876 | 5,537 |
| Cherokee | Georgia | 10 | 273,696 | 364 |
| Rockingham | New Hampshire | 559 | 273,232 | 32,389 |
| Tuscaloosa | Alabama | 10 | 272,754 | 118 |
| McHenry | Illinois | 307 | 271,051 | 11,554 |
| Madison | Illinois | 68 | 268,778 | 1,940 |
| Yakima | Washington | 220 | 268,022 | 12,104 |
| Merced | California | 119 | 267,234 | 1,403 |
| St. Tammany Parish | Louisiana | 213 | 266,825 | 7,149 |
| Greene | Missouri | 82 | 265,439 | 7,132 |
| Monroe | New York | 19 | 263,490 | 190 |
| Westmoreland | Pennsylvania | 82 | 262,918 | 12,979 |
| Yolo | California | 90 | 260,218 | 2,443 |
| Washington | Minnesota | 195 | 259,368 | 1,652 |
| Whatcom | Washington | 185 | 258,702 | 11,873 |
| Dutchess | New York | 550 | 258,307 | 28,815 |
| St. Clair | Illinois | 54 | 258,141 | 3,100 |
| Winnebago | Illinois | 196 | 255,966 | 12,949 |
| Fayette | Pennsylvania | 41 | 255,694 | 10,137 |
| Minnehaha | South Dakota | 15 | 254,737 | 868 |
| Jefferson | Texas | 23 | 252,985 | 2,290 |
| Ellis | Texas | 34 | 251,348 | 2,967 |
| Dona Ana | New Mexico | 68 | 251,275 | 7,336 |
| Williamson | Tennessee | 7 | 250,051 | 510 |
| Caddo Parish | Louisiana | 48 | 249,641 | 5,038 |
| Cumberland | Pennsylvania | 99 | 249,438 | 10,230 |
| Charlotte | Florida | 29 | 248,550 | 1,094 |
| Brown | Wisconsin | 149 | 246,872 | 2,891 |
| Washington | Utah | 61 | 246,683 | 14,833 |
| Houston | Georgia | 10 | 246,533 | 235 |
| Ottawa | Michigan | 233 | 246,531 | 3,476 |
| Arlington | Virginia | 4 | 244,747 | 65 |
| Warren | Ohio | 21 | 242,137 | 4,221 |
| New Hanover | North Carolina | 67 | 237,607 | 5,068 |
| Leon | Florida | 41 | 236,457 | 1,017 |
| Brunswick | North Carolina | 27 | 234,624 | 1,546 |
| Comal | Texas | 95 | 233,238 | 7,576 |
| Johnson | Texas | 61 | 232,795 | 4,743 |
| Butte | California | 88 | 231,825 | 1,512 |
| Mohave | Arizona | 119 | 231,271 | 20,586 |
| Lake | Ohio | 20 | 230,589 | 1,095 |
| Muscogee | Georgia | 4 | 229,453 | 15 |
| Hamilton | Indiana | 66 | 229,377 | 6,714 |
| Mahoning | Ohio | 75 | 228,296 | 4,611 |
| Boone | Missouri | 13 | 228,201 | 462 |
| Alachua | Florida | 64 | 226,130 | 2,317 |