Colorado tap water
4 of 155 Colorado water systems with full PFAS testing (3%) averaged above a 2024 federal PFAS level at one or more sampling points.
- 1,049 active community water systems in the EPA file; 146 serve 3,300+ people and have a full PFAS set.
- 256 systems had at least one health-based violation since 2021-10-26.
- 2 systems report a lead 90th percentile above 15 ppb (some results are old; check each system page).
Largest systems
| System | People served | PFAS above a 2024 level? | Health-based violations since 2021-10-26 |
|---|---|---|---|
| Denver Water Board | 1,287,000 | No | 0 |
| Aurora City of | 533,407 | No | 0 |
| Colorado Springs Utilities | 464,111 | No | 0 |
| Thornton City of | 226,465 | No | 0 |
| Westminster City of | 202,078 | No | 0 |
| Ft Collins City of | 179,901 | No | 0 |
| Arvada City of | 171,610 | No | 0 |
| Boulder City of | 166,080 | No | 0 |
Counties
El Paso County17 systems with full PFAS testingWeld County15 systems with full PFAS testingLarimer County12 systems with full PFAS testingDouglas County11 systems with full PFAS testing
All 27 utilities with a page in Colorado
- Arvada City of 171,610
- Aurora City of 533,407
- Boulder City of 166,080
- Brighton City of 56,304
- Broomfield City and County of 106,153
- Castle Rock Town of 110,298
- Colorado Springs Utilities 464,111
- Consolidated Mutual Maple Grove 81,400
- Denver Water Board 1,287,000
- Eagle River Wsd 51,515
- East Cherry Creek Valley Wsd 66,130
- Englewood City of 59,904
- Erie Town of 47,444
- Ft Collins City of 179,901
- Ft Collins Loveland Wd 63,532
- Greeley City of 132,310
- Highlands Ranch Wsd 103,444
- Longmont City of 104,178
- Loveland City of 91,077
- Northglenn City of 48,927
- Parker Wsd 75,949
- Pueblo Board of Ww 114,070
- South Adams County Wsd 75,559
- Thornton City of 226,465
- US department of the Army Fort Carson 48,000
- Ute Wcd 92,580
- Westminster City of 202,078
Why not "the state's water quality"? You drink from one utility, not a state. Rollups count systems, not people, so one large utility counts the same as a small one. Use the system pages for your actual water.
Not medical or legal advice. UCMR 5 results are screening data, not compliance determinations.
Sources and freshness
Public-water-system facts, violations and lead/copper results: EPA ECHO SDWA download (SDWIS snapshot 2026-10-13). PFAS and lithium results: EPA UCMR 5 final data (sampling 2023–2025). Both are U.S. government works, downloaded 2026-10-26. Numbers are computed by the published method; the same fields are in the open data files.