Colorado drinking water quality
Colorado has 2,218 active public water systems serving 7.5 million people. 1,325 of them, 60%, had at least one EPA violation in the past three years, 406 have an unresolved violation today, and 33 are designated serious violators by the EPA.
Active systems
2,218
in 64 counties
People served
7.5M
1,060 community systems serve 7.2M
Violations, past 3 years
1,325
60% of active systems
Serious violators
33
95 systems carry a health flag
Largest counties
All 64 countiesLargest community water systems
All 2,218 systems| System | Serves | Status |
|---|---|---|
| Denver Water Board Denver County |
1,287,000 | |
| Aurora City of Arapahoe County |
533,407 | |
| Colorado Springs Utilities El Paso County |
464,111 | |
| Thornton City of Adams County |
226,465 | |
| Westminster City of Adams County |
202,078 | |
| FT Collins City of Larimer County |
179,901 | |
| Arvada City of Jefferson County |
171,610 | |
| Boulder City of Boulder County |
166,080 | |
| Greeley City of Weld County |
132,310 | |
| Pueblo Board of WW Pueblo County |
114,070 |
About the Colorado data
Retrieved from EPA ECHO on Oct 11, 2026. EPA records for Colorado systems do not include town names, so searches here match on ZIP code, street address, or county.