Iowa drinking water quality
Iowa has 1,804 active public water systems serving 3.2 million people. 705 of them, 39%, had at least one EPA violation in the past three years, 207 have an unresolved violation today, and 12 are designated serious violators by the EPA.
Active systems
1,804
in 99 counties
People served
3.2M
1,083 community systems serve 3M
Violations, past 3 years
705
39% of active systems
Serious violators
12
15 systems carry a health flag
Largest counties
All 99 counties| County | People served | Systems | With violations |
|---|---|---|---|
| Polk | 565,617 | 39 | 10 |
| Linn | 224,589 | 82 | 34 |
| Johnson | 193,432 | 126 | 61 |
| Scott | 172,135 | 78 | 23 |
| Black Hawk | 161,165 | 18 | 5 |
| Story | 158,728 | 21 | 9 |
| Dallas | 147,667 | 23 | 10 |
| Woodbury | 99,514 | 32 | 7 |
| Dubuque | 92,880 | 74 | 30 |
| Pottawattamie | 85,108 | 33 | 16 |
Largest community water systems
All 1,804 systems| System | Serves | Status |
|---|---|---|
| Des Moines Water Works Polk County |
246,055 | |
| Iowa-American Wtr Co-Davenport Scott County |
147,720 | |
| Cedar Rapids Water Department Linn County |
142,364 | |
| Sioux City Water Supply Woodbury County |
85,791 | |
| Ankeny, City of Polk County |
76,207 | |
| West Des Moines Water Works Dallas County |
73,959 | |
| Waterloo Water Works Black Hawk County |
69,504 | |
| Iowa City Water Department Johnson County |
68,753 | |
| Council Bluffs Water Works Pottawattamie County |
64,447 | |
| Dubuque Water Works Dubuque County |
59,667 |
About the Iowa data
Retrieved from EPA ECHO on Oct 11, 2026.