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Colorado Water Quality
423
Utilities in database
7.1M
Residents served
25%
On private wells
3
Key contaminants tracked
Drinking Water in Colorado
Colorado has 423 community water systems serving approximately 7.1 million residents. Primary water sources include surface water. The most commonly reported contaminants include disinfection byproducts, lead, arsenic. 25% of Colorado residents rely on private wells. CDPHE holds primary enforcement authority under the Safe Drinking Water Act.
Utilities in Colorado
1–25 of 423Denver Water Board
CO0116001 · 1,287,000 served
City of Aurora
CO0103005 · 533,407 served
Colorado Springs Utilities
CO0121150 · 464,111 served
City of Thornton
CO0101150 · 226,465 served
City of Westminster
CO0101170 · 202,078 served
City of Ft Collins
CO0135291 · 179,901 served
City of Arvada
CO0130001 · 171,610 served
City of Boulder
CO0107152 · 166,080 served
City of Greeley
CO0162321 · 132,310 served
Pueblo Board of Ww
CO0151500 · 114,070 served
Town of Castle Rock
CO0118010 · 106,822 served
County of Broomfield City and
CO0107155 · 106,153 served
Highlands Ranch Wsd
CO0118015 · 103,444 served
City of Longmont
CO0107485 · 102,866 served
City of Loveland
CO0135485 · 95,471 served
Ute Wcd
CO0139791 · 92,580 served
Consolidated Mutual Maple Grove
CO0130020 · 81,400 served
Parker Wsd
CO0118040 · 75,949 served
South Adams County Wsd
CO0101140 · 75,559 served
East Cherry Creek Valley Wsd
CO0103035 · 66,130 served
Ft Collins Loveland Wd
CO0135292 · 63,532 served
City of Englewood
CO0103045 · 57,332 served
City of Brighton
CO0101025 · 56,304 served
Southgate Wsd
CO0103721 · 55,000 served
Eagle River Wsd
CO0119802 · 51,515 served
Key Contaminant Concerns in Colorado
Lead
Lead is a naturally occurring heavy metal that was widely used in plumbing infrastructure until it was banned for new installations in 1986. An estimated 9.2 million lead service lines still connect homes to public water mains across the United States, along with millions of homes with lead solder in their internal plumbing.
DBPs
When utilities add chlorine to water to kill pathogens, it reacts with dissolved organic matter — leaves, algae, soil — to produce disinfection byproducts (DBPs). Over 600 DBPs have been identified. The EPA regulates two groups: total trihalomethanes (TTHMs, including chloroform) and haloacetic acids (HAA5). DBP levels tend to be highest in surface water systems and in warm months when organic matter is elevated.
Arsenic
Arsenic (As) occurs naturally in rock and soil, dissolving into groundwater through natural weathering processes. Inorganic arsenic — the form found in drinking water — is a known human carcinogen. The western United States has particularly arsenic-rich geological formations, but elevated levels have been found in 48 states. Arsenic is tasteless and odorless.
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Data source: Utility data from EPA SDWIS. 423 active community water systems ingested. CCR contaminant data ingestion in progress.
Last updated: 2026-04-18