Denver County, Colorado: drinking water report. Denver County is coextensive with the City and County of Denver, with about 713,000 residents.
Denver County is coextensive with the City and County of Denver, with about 713,000 residents. Denver Water – one of the oldest and largest water utilities in the West – draws from a network of mountain reservoirs and tunnels that collect snowmelt from the Front Range and Continental Divide. The system's source water is among the cleanest of any major U.S. city, pulled from high-elevation watersheds with minimal development.
Denver Water's mountain source water consistently meets all standards with wide margins. According to Denver Water's 2024 water quality report, the system's distribution water showed no detections above MCLs for any regulated contaminant. The utility's biggest operational challenge is managing the variable supply that comes with Western water rights and climate-driven snowpack fluctuation.
Denver International Airport – one of the largest airports in the world – has documented AFFF use at its fire training facility. Colorado DPHE's 2024 PFAS investigation found PFOS at 18 ppt in monitoring wells near the airport. The airport is in northeastern Denver, and the contamination affects groundwater in the area between the airport and the city's eastern neighborhoods.
Denver's mountain water supply is a genuine asset – few major cities enjoy source water this clean. The primary concern for most residents is lead from older service lines and building plumbing. Denver Water has been replacing lead service lines under a 15-year program.
Check your water for data at your address, including lead service line status. For homes with older plumbing, a certified lead filter provides daily protection. For PFAS near the airport, reverse osmosis adds another layer. Our water filter guide covers both. Get your detailed report for trends, and visit our Colorado page for statewide context.
Drinking water is one exposure route. These federal datasets also cover Denver County, CO.
The EPA places Denver County, CO in Zone 1 - the EPA's highest-risk category, where the predicted average indoor radon level is above 4 pCi/L. Zone maps predict an area's radon potential from geology and existing indoor readings; they say nothing about a specific house. Testing is the only way to know your own level.
59% of homes in Denver County, CO were built before 1980, and 23% before 1950. Residential lead paint was banned in 1978, so housing age is the strongest available proxy for lead-paint exposure. This describes the county's housing stock, not any one home.
Modelled annual fine-particle pollution (PM2.5) in Denver County, CO averages 6.6 µg/m³, within the EPA's annual standard of 9 µg/m³. These are CDC modelled county estimates rather than readings from a specific monitor.
How radon zones work · Air quality by county · Lead exposure guide