Colorado tap water quality
1,061 community water systems serving 7.2 million people.
Data: U.S. EPA · How we read the data · How we check it
PFAS: EPA's 2023–2025 testing. Lead: results from the last five years. 39 more systems have no recent lead results in EPA's database.
Water systems with PFAS above the federal limit
Based on EPA's UCMR 5 results (2023–2025) compared to the April 2024 limits, the way EPA compares them. Systems have until 2029 to comply. Largest first.
- City of Brighton56,304 people · Purchased surface water · ColoradoPFOS above limitAlso: Total trihalomethanes (TTHM) violation · PFOA detected · PFHxS detected
- Widefield Water & Sanitation District27,640 people · Purchased surface water · ColoradoPFOA above limitAlso: PFOS above limit · PFHxS above limit · PFAS Hazard Index above limit · 1 health-based violation since 2016
- Snake River Water District9,900 people · Groundwater · ColoradoPFOS above limitAlso: PFOA detected · PFHxS detected
- Todd Creek Village Metropolitan District7,363 people · Groundwater under influence of surface water · ColoradoPFOS above limitAlso: PFHxS detected · Lithium above screening level
Colorado PFAS report: chart, rankings and data to download →
Largest water systems in Colorado
- Denver Water Board1.3 million people · Surface water · ColoradoNo PFAS above limits
- City of Aurora533,407 people · Surface water · ColoradoLithium above screening level
- Colorado Springs Utilities464,111 people · Surface water · ColoradoLithium above screening level
- City of Thornton226,465 people · Surface water · ColoradoPFOA detectedAlso: PFOS detected · PFHxS detected · Lithium above screening level
- City of Westminster202,078 people · Surface water · ColoradoLithium above screening level
- City of Ft Collins179,901 people · Surface water · ColoradoNo PFAS above limitsAlso: 1 health-based violation since 2016
- City of Arvada171,610 people · Surface water · ColoradoNo PFAS above limits
- City of Boulder166,080 people · Surface water · ColoradoHaloacetic acids (HAA5) violations
- City of Greeley132,310 people · Surface water · ColoradoLithium above screening level
- Pueblo Board of Water Works114,070 people · Surface water · ColoradoNo PFAS above limits
- Town of Castle Rock110,298 people · Surface water · ColoradoLithium above screening level
- County of Broomfield City and106,153 people · Surface water · ColoradoNo PFAS above limitsAlso: 2 health-based violations since 2016
- City of Longmont104,178 people · Surface water · ColoradoNo PFAS above limits
- Highlands Ranch Water & Sanitation District103,444 people · Surface water · ColoradoLithium above screening level
- Ute Water Conservancy District92,580 people · Surface water · ColoradoNo PFAS above limits
Colorado cities and towns
- Arvada
- Aurora
- Boulder
- Brighton
- Broomfield
- Castle Rock
- Centennial
- Colorado Springs
- Commerce City
- Denver
- Englewood
- Erie
- Fort Collins
- Fountain
- Grand Junction
- Greeley
- Lafayette
- Lakewood
- Littleton
- Longmont
- Loveland
- Northglenn
- Parker
- Pueblo
- Thornton
- Westminster
- Wheat Ridge
- Windsor
Most health-based violations since 2016
- May Valley WA Water System1,500 people · Groundwater · ColoradoRadium (combined 226/228) violationsAlso: Gross alpha violations
- Valley Water Company270 people · Groundwater · ColoradoRadium (combined 226/228) violationsAlso: Gross alpha violations
- South Swink Water Authority622 people · Groundwater · ColoradoRadium (combined 226/228) violationsAlso: Gross alpha violations
- Beehive Water Association154 people · Groundwater · ColoradoRadium (combined 226/228) violations
- Patterson Valley Water Company96 people · Groundwater · ColoradoRadium (combined 226/228) violationsAlso: Gross alpha violations · Lithium above screening level
- Eureka Water Company498 people · Groundwater · ColoradoRadium (combined 226/228) violationsAlso: Gross alpha violations
- Vroman Water Company125 people · Groundwater · ColoradoRadium (combined 226/228) violationsAlso: Gross alpha violations
- Fayette Water Company75 people · Groundwater · ColoradoRadium (combined 226/228) violationsAlso: Gross alpha violations
- Town of Manzanola497 people · Groundwater · ColoradoRadium (combined 226/228) violationsAlso: Uranium violations · Gross alpha violations
- Town of Rye745 people · Surface water · ColoradoHaloacetic acids (HAA5) violationsAlso: Total trihalomethanes (TTHM) violations
- Riverside Water Company90 people · Groundwater · ColoradoRadium (combined 226/228) violationsAlso: Lead near 2027 level
- City of Burlington3,720 people · Groundwater · ColoradoNitrate violationsAlso: Lithium above screening level
- East End WA Water System70 people · Groundwater · ColoradoRadium (combined 226/228) violationsAlso: Coliform bacteria violations
- Sun Meadow Estates Water System75 people · Groundwater · ColoradoTotal trihalomethanes (TTHM) violationsAlso: Uranium violations · Gross alpha violations
- Town of Cheraw254 people · Groundwater · ColoradoRadium (combined 226/228) violationsAlso: Gross alpha violations
All Colorado utilities on this site
Every Colorado system serving 50,000+ people or with PFAS above a federal limit, A to Z. Download all 1,061 systems as CSV.
- City of Arvada
- City of Aurora
- City of Boulder
- City of Brighton
- City of Englewood
- City of Ft Collins
- City of Greeley
- City of Longmont
- City of Loveland
- City of Thornton
- City of Westminster
- Colorado Springs Utilities
- Consolidated Mutual Maple Grove Water System
- County of Broomfield City and
- Denver Water Board
- Eagle River Water & Sanitation District
- East Cherry Creek Valley Water & Sanitation District
- Ft Collins Loveland Water District
- Highlands Ranch Water & Sanitation District
- Parker Water & Sanitation District
- Pueblo Board of Water Works
- Snake River Water District
- South Adams County Water & Sanitation District
- Southgate Water & Sanitation District
- Todd Creek Village Metropolitan District
- Town of Castle Rock
- Ute Water Conservancy District
- Widefield Water & Sanitation District
Questions
Does Colorado tap water have PFAS?
EPA tested 158 community water systems in Colorado for 29 PFAS between 2023 and 2025. 18 had at least one regulated PFAS detected, and 4 had an entry-point average above a 2024 federal limit. Those 4 systems serve about 101,207 people (1% of people on community water in Colorado). Systems have until 2029 to meet the limits.
How many Colorado water systems have violations?
388 systems in Colorado had at least one health-based violation since 2016 (2,901 violations in total). 415 violations are currently listed as unaddressed.
Which Colorado water systems are over the lead action level?
2 systems had a lead 90th percentile above the 15 ppb action level in their most recent results from the last five years. Another 39 systems have no lead results in EPA's database from the last five years. Lead depends on each home's pipes, so a test of your own tap is the only way to know your level.
Source: U.S. EPA drinking water records and PFAS testing (UCMR 5). How we read the data.