Missouri water quality by county
115 counties with public water systems. Pick a county to see every system that serves it.
| County | Active systems | People served | Share with violations, 3 yr | Serious violators | Health flags |
|---|---|---|---|---|---|
| Adair County | 4 | 25,680 | 0 | 0 | |
| Andrew County | 11 | 106,624 | 0 | 0 | |
| Atchison County | 7 | 4,315 | 0 | 0 | |
| Audrain County | 7 | 28,422 | 0 | 0 | |
| Barry County | 93 | 30,479 | 1 | 1 | |
| Barton County | 5 | 15,802 | 0 | 0 | |
| Bates County | 15 | 18,899 | 0 | 0 | |
| Benton County | 87 | 13,814 | 0 | 1 | |
| Bollinger County | 16 | 4,849 | 0 | 0 | |
| Boone County | 13 | 229,905 | 0 | 0 | |
| Buchanan County | 7 | 92,133 | 0 | 0 | |
| Butler County | 14 | 35,803 | 0 | 0 | |
| Caldwell County | 11 | 19,478 | 0 | 0 | |
| Callaway County | 14 | 40,124 | 0 | 0 | |
| Camden County | 237 | 58,833 | 1 | 2 | |
| Cape Girardeau County | 31 | 73,750 | 0 | 0 | |
| Carroll County | 7 | 8,309 | 0 | 0 | |
| Carter County | 9 | 3,732 | 0 | 0 | |
| Cass County | 33 | 667,465 | 1 | 0 | |
| Cedar County | 33 | 18,574 | 0 | 2 | |
| Chariton County | 5 | 4,263 | 1 | 0 | |
| Christian County | 42 | 61,849 | 0 | 0 | |
| Clark County | 4 | 10,590 | 0 | 0 | |
| Clay County | 22 | 678,521 | 0 | 0 | |
| Clinton County | 10 | 582,552 | 1 | 0 | |
| Cole County | 17 | 73,889 | 0 | 0 | |
| Cooper County | 8 | 12,993 | 0 | 0 | |
| Crawford County | 38 | 19,407 | 0 | 0 | |
| Dade County | 21 | 13,998 | 0 | 0 | |
| Dallas County | 17 | 5,315 | 0 | 0 | |
| Daviess County | 12 | 13,464 | 0 | 0 | |
| DeKalb County | 9 | 103,613 | 0 | 0 | |
| Dent County | 16 | 8,693 | 0 | 0 | |
| Douglas County | 9 | 3,652 | 0 | 0 | |
| Dunklin County | 13 | 36,188 | 0 | 1 | |
| Franklin County | 85 | 71,330 | 0 | 1 | |
| Gasconade County | 17 | 8,058 | 1 | 2 | |
| Gentry County | 7 | 6,355 | 0 | 0 | |
| Greene County | 83 | 265,436 | 0 | 1 | |
| Grundy County | 5 | 10,160 | 1 | 0 | |
| Harrison County | 9 | 12,405 | 0 | 0 | |
| Henry County | 13 | 23,361 | 1 | 0 | |
| Hickory County | 45 | 7,583 | 1 | 0 | |
| Holt County | 8 | 5,976 | 0 | 0 | |
| Howard County | 6 | 8,282 | 0 | 0 | |
| Howell County | 17 | 24,307 | 0 | 0 | |
| Iron County | 23 | 6,544 | 1 | 0 | |
| Jackson County | 25 | 960,275 | 0 | 0 | |
| Jasper County | 40 | 141,918 | 1 | 0 | |
| Jefferson County | 98 | 188,323 | 1 | 2 | |
| Johnson County | 16 | 66,549 | 0 | 0 | |
| Knox County | 2 | 4,961 | 0 | 0 | |
| Laclede County | 15 | 32,039 | 0 | 1 | |
| Lafayette County | 15 | 36,111 | 2 | 0 | |
| Lawrence County | 35 | 20,171 | 1 | 0 | |
| Lewis County | 5 | 7,015 | 0 | 0 | |
| Lincoln County | 48 | 45,636 | 0 | 1 | |
| Linn County | 9 | 14,642 | 1 | 0 | |
| Livingston County | 8 | 19,091 | 0 | 0 | |
| Macon County | 7 | 21,158 | 0 | 0 | |
| Madison County | 9 | 6,987 | 0 | 0 | |
| Maries County | 10 | 3,743 | 0 | 1 | |
| Marion County | 3 | 25,603 | 0 | 0 | |
| McDonald County | 27 | 13,946 | 0 | 1 | |
| Mercer County | 3 | 4,801 | 0 | 0 | |
| Miller County | 53 | 13,029 | 1 | 2 | |
| Mississippi County | 6 | 12,823 | 0 | 0 | |
| Moniteau County | 13 | 10,118 | 1 | 1 | |
| Monroe County | 5 | 10,940 | 1 | 0 | |
| Montgomery County | 23 | 18,565 | 0 | 0 | |
| Morgan County | 76 | 13,651 | 1 | 1 | |
| New Madrid County | 15 | 15,503 | 1 | 0 | |
| Newton County | 42 | 23,863 | 2 | 2 | |
| Nodaway County | 13 | 20,154 | 0 | 1 | |
| Oregon County | 7 | 4,746 | 0 | 0 | |
| Osage County | 15 | 9,882 | 0 | 1 | |
| Ozark County | 27 | 4,343 | 1 | 0 | |
| Pemiscot County | 7 | 17,383 | 0 | 0 | |
| Perry County | 15 | 14,294 | 0 | 0 | |
| Pettis County | 32 | 29,485 | 1 | 0 | |
| Phelps County | 33 | 30,448 | 0 | 0 | |
| Pike County | 6 | 16,023 | 0 | 0 | |
| Platte County | 21 | 607,525 | 0 | 1 | |
| Polk County | 22 | 15,734 | 0 | 0 | |
| Pulaski County | 25 | 64,579 | 2 | 0 | |
| Putnam County | 4 | 4,895 | 0 | 0 | |
| Ralls County | 4 | 15,813 | 0 | 0 | |
| Randolph County | 6 | 27,721 | 0 | 0 | |
| Ray County | 9 | 24,631 | 0 | 0 | |
| Reynolds County | 30 | 4,355 | 1 | 0 | |
| Ripley County | 8 | 8,651 | 0 | 1 | |
| Saline County | 13 | 29,479 | 1 | 0 | |
| Schuyler County | 4 | 4,740 | 0 | 0 | |
| Scotland County | 2 | 5,182 | 0 | 0 | |
| Scott County | 18 | 34,163 | 2 | 1 | |
| Shannon County | 22 | 6,529 | 0 | 0 | |
| Shelby County | 5 | 6,607 | 0 | 0 | |
| St. Charles County | 55 | 1,427,837 | 0 | 1 | |
| St. Clair County | 16 | 9,722 | 0 | 0 | |
| St. Francois County | 45 | 55,319 | 0 | 1 | |
| St. Louis County | 25 | 1,151,644 | 0 | 1 | |
| St. Louis city | 1 | 304,709 | 0 | 0 | |
| Ste. Genevieve County | 17 | 13,959 | 0 | 0 | |
| Stoddard County | 19 | 23,353 | 0 | 0 | |
| Stone County | 241 | 47,165 | 0 | 2 | |
| Sullivan County | 8 | 8,393 | 0 | 0 | |
| Taney County | 117 | 74,563 | 1 | 2 | |
| Texas County | 12 | 15,719 | 0 | 0 | |
| Vernon County | 9 | 23,750 | 0 | 0 | |
| Warren County | 31 | 25,792 | 0 | 1 | |
| Washington County | 41 | 9,169 | 0 | 0 | |
| Wayne County | 32 | 9,333 | 1 | 0 | |
| Webster County | 29 | 20,029 | 0 | 0 | |
| Worth County | 4 | 2,607 | 0 | 0 | |
| Wright County | 11 | 8,252 | 0 | 0 |
under 30% 30 to 59% 60% and over
About this data
Share with violations counts any violation in the past three years, including monitoring and reporting lapses. Counts cover active systems; systems serving more than one county are counted in each.
Source: the U.S. EPA's Enforcement and Compliance History Online system (ECHO), which publishes the federal Safe Drinking Water Information System. EPA's terms and values are shown as published. The Missouri records are from EPA's data refresh of Oct 7, 2026; EPA refreshes this data quarterly, and states report to EPA with a lag of three to six months, so the newest violations may not appear yet. Retrieved from ECHO on Oct 11, 2026.