Missouri drinking water quality
Missouri has 2,835 active public water systems serving 5.9 million people. 1,807 of them, 64%, had at least one EPA violation in the past three years, 601 have an unresolved violation today, and 32 are designated serious violators by the EPA.
Active systems
2,835
in 115 counties
People served
5.9M
1,434 community systems serve 5.7M
Violations, past 3 years
1,807
64% of active systems
Serious violators
32
35 systems carry a health flag
Largest counties
All 115 counties| County | People served | Systems | With violations |
|---|---|---|---|
| St. Charles | 1,427,837 | 55 | 32 |
| St. Louis | 1,151,644 | 25 | 13 |
| Jackson | 960,275 | 25 | 19 |
| Clay | 678,521 | 22 | 15 |
| Cass | 667,465 | 33 | 22 |
| Platte | 607,525 | 21 | 14 |
| Clinton | 582,552 | 10 | 6 |
| St. Louis city | 304,709 | 1 | 1 |
| Greene | 265,436 | 83 | 50 |
| Boone | 229,905 | 13 | 8 |
Largest community water systems
All 2,835 systems| System | Serves | Status |
|---|---|---|
| MO American ST Louis ST Charles Counties St. Charles County |
1,111,000 | |
| Kansas City PWS Cass County |
553,295 | |
| ST Louis City PWS St. Louis city |
304,709 | |
| City Utilities of Springfield Greene County |
210,898 | |
| City of Columbia Utilities Boone County |
126,254 | |
| Independence PWS Jackson County |
120,000 | |
| ST Charles County Pwsd 2 St. Charles County |
100,587 | |
| Lees Summit PWS Jackson County |
99,400 | |
| MO American ST Joseph Andrew County |
89,171 | |
| ST Charles PWS St. Charles County |
78,961 |
About the Missouri data
Retrieved from EPA ECHO on Oct 11, 2026. EPA records for Missouri systems do not include town names, so searches here match on ZIP code, street address, or county.