States → Colorado
State profile · EPA SDWIS + UCMR5
Colorado Drinking Water Quality
2,193 public water systems serve 7,473,456 people across Colorado, with every Safe Drinking Water Act violation and UCMR5 PFAS result on record.
- 2,193
- Water systems
- 238,796
- Total violations
- 92.6%
- Systems w/ a violation
- 60.1%
- PFAS detection rate
The verdict
Across Colorado, 2,030 of 2,193 water systems (92.6%) carry at least one EPA violation, and 98 of 163 UCMR5-tested systems show PFAS.
- 238,796
- Total EPA violations on record
- 13%
- Health-based (MCL / treatment)
- 92.6%
- Systems with ≥1 violation
- 60.1%
- UCMR5 PFAS detection rate
Water Systems
2,193
Total Violations
238,796
Violation Rate
92.6%
PFAS Detection
60.1%
98 of 163 tested
Violation Composition
How Colorado's 238,796 violations break down by type, per EPA SDWIS classification.
Health-based (30,589) Monitoring/Reporting (208,207)
| Metric | Value | Share |
|---|---|---|
| Public water systems | 2,193 | - |
| Population served | 7,473,456 | - |
| Total violations | 238,796 | 100% |
| Health-based violations | 30,589 | 12.8% |
| Systems with violations | 2,030 | 92.6% |
| PFAS detection rate | 98 of 163 | 60.1% |
Health-based violations indicate the contaminant exceeded an EPA Maximum Contaminant Level (MCL) or treatment-technique requirement. Monitoring/reporting violations indicate procedural issues (missed tests, late reports) - not necessarily a contamination event.
Largest Water Systems
Denver Water Board
Denver, CO · 1,287,000 served
Aurora City Of
Aurora, CO · 533,407 served
Colorado Springs Utilities
Colorado Springs, CO · 464,111 served
Thornton City Of
Thornton, CO · 226,465 served
Westminster City Of
Westminster, CO · 202,078 served
Ft Collins City Of
Fort Collins, CO · 179,901 served
Arvada City Of
Arvada, CO · 171,610 served
Boulder City Of
Boulder, CO · 166,080 served
Greeley City Of
Greeley, CO · 132,310 served
Pueblo Board of Ww
Pueblo, CO · 114,070 served
Castle Rock Town Of
Castle Rock, CO · 106,822 served
Broomfield City and County Of
Broomfield, CO · 106,153 served
Highlands Ranch WSD
Highlands Ranch, CO · 103,444 served
Longmont City Of
Longmont, CO · 102,866 served
Loveland City Of
Loveland, CO · 95,471 served
Ute Wcd
Grand Junction, CO · 91,186 served
Consolidated Mutual Maple Grove
Lakewood, CO · 81,400 served
Parker WSD
Parker, CO · 75,949 served
South Adams County WSD
Commerce City, CO · 74,341 served
East Cherry Creek Valley WSD
Aurora, CO · 66,130 served
Most Violations
#1 Happy Camper RV Park Pagosa Springs
2,875 #2 Creekside South Estates Metro District Windsor
2,820 #3 Estates at Bromley Hudson
2,787 #4 May Valley WA Wiley
2,247 #5 Pacheco Trailer Park Monte Vista
2,060 #6 Paint Brush Hills Falcon
1,810 #7 East Cherry Creek Valley WSD Aurora
1,783 #8 Burlington City Of Burlington
1,699 #9 Seedorf WS Yuma
1,606 #10 Parkville WD Leadville
1,268 #11 Gaytan WS Yuma
1,247 #12 Fruitland Domestic WC Hotchkiss
1,196 #13 Wishing Well Motel Castle Rock
1,181 #14 Florissant WSD Florissant
1,146 #15 Meridian Point Church Peyton
1,128 Counties in Colorado
Denver
5 systems · 1,312,794 served
· 487 violations
Arapahoe
40 systems · 864,434 served
· 5,553 violations
El Paso
140 systems · 757,938 served
· 21,020 violations
Adams
86 systems · 711,442 served
· 11,205 violations
Jefferson
113 systems · 577,729 served
· 5,182 violations
Larimer
136 systems · 519,497 served
· 9,218 violations
Boulder
82 systems · 428,472 served
· 7,231 violations
Douglas
73 systems · 417,473 served
· 7,411 violations
Weld
77 systems · 359,543 served
· 4,558 violations
Pueblo
29 systems · 167,384 served
· 4,552 violations
Mesa
37 systems · 163,215 served
· 2,022 violations
Broomfield
3 systems · 108,783 served
· 24 violations
Eagle
47 systems · 103,381 served
· 4,199 violations
Summit
42 systems · 89,593 served
· 4,364 violations
La Plata
110 systems · 62,563 served
· 9,256 violations
Garfield
86 systems · 61,334 served
· 7,428 violations
Fremont
32 systems · 57,902 served
· 2,460 violations
Montrose
26 systems · 56,323 served
· 3,807 violations
Grand
79 systems · 56,214 served
· 6,442 violations
Pitkin
50 systems · 53,372 served
· 6,062 violations
Routt
50 systems · 50,449 served
· 5,239 violations
Montezuma
18 systems · 31,851 served
· 1,218 violations
Morgan
8 systems · 28,903 served
· 1,287 violations
Gunnison
74 systems · 28,235 served
· 4,404 violations
Delta
42 systems · 27,718 served
· 7,243 violations
Clear Creek
31 systems · 26,778 served
· 2,262 violations
Chaffee
70 systems · 24,956 served
· 5,369 violations
Teller
51 systems · 23,723 served
· 9,700 violations
Gilpin
21 systems · 22,561 served
· 989 violations
San Miguel
20 systems · 22,019 served
· 4,325 violations
Showing top 30 of 64 counties.
Drinking Water Guides
Frequently Asked Questions
How many water systems are in Colorado? ▼
Colorado has 2,193 public water systems serving approximately 7,473,456 people. These include community water systems, non-transient non-community systems, and transient non-community systems regulated under the Safe Drinking Water Act.
How many drinking water violations are in Colorado? ▼
Colorado has 238,796 total drinking water violations on record, with 30,589 classified as health-based violations. 92.6% of water systems in the state have at least one violation.
Has PFAS been found in Colorado drinking water? ▼
Of 163 water systems tested for PFAS in Colorado, 98 had PFAS detected, a 60.1% detection rate. PFAS are persistent "forever chemicals" that do not break down in the environment.
What is the violation rate for Colorado water systems? ▼
Colorado's violation rate is 92.6%. This measures the percentage of public water systems that have at least one recorded violation in the EPA SDWIS database, including both health-based and monitoring/reporting violations.
Where does this Colorado water data come from? ▼
All drinking water data comes from the EPA Safe Drinking Water Information System (SDWIS) and the UCMR5 PFAS monitoring program. SDWIS is the federal database that tracks compliance for all public water systems regulated under the Safe Drinking Water Act.
Data Sources & Methodology
Drinking water violation data from the EPA Safe Drinking Water Information System (SDWIS). PFAS testing data from the UCMR5 monitoring program. SDWIS tracks all public water systems regulated under the Safe Drinking Water Act.
Read our methodology - how this data is sourced, computed, and verified.
Related
Data sourced from EPA SDWIS and UCMR5 PFAS monitoring data. See our methodology for details. Retrieved and formatted by PlainWater Editorial
Every figure on PlainWater is rendered directly from EPA SDWIS drinking-water data, no number is typed in by an editor. This page draws directly on EPA SDWIS data, no figure is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error.