Douglas County, Colorado: drinking water report. Douglas County sits between Denver and Colorado Springs, home to about 370,000 residents.
Douglas County sits between Denver and Colorado Springs, home to about 370,000 residents. Water sources are complex – some communities receive treated surface water from Denver Water or Aurora Water via wholesale agreements, while others rely on the Denver Basin aquifers (Dawson, Denver, Arapahoe, and Laramie-Fox Hills formations). The county's rapid suburban growth has strained groundwater resources, and aquifer levels have been declining for decades.
The Denver Basin aquifers are non-renewable – they recharge at a rate far slower than current extraction. Several water districts in Douglas County have documented declining well levels and are actively seeking alternative surface water supplies. Water quality from these deep aquifers is generally good, but naturally occurring uranium and radium have been detected in some wells.
UCMR5 data shows low-level PFAS detections in some county systems. According to the Colorado Department of Public Health and Environment's 2024 monitoring data, PFAS readings in Douglas County were below proposed federal MCLs. The county does not host major military installations, limiting point-source PFAS contamination.
If your provider relies on Denver Basin aquifer water, supply sustainability is a concern even if current quality is good. Water conservation directly extends the life of these non-renewable sources.
Check your water for current data in your area. For naturally occurring radionuclides, reverse osmosis is the most effective household treatment. Our water filter guide covers which systems handle these specific contaminants. Pull your detailed report, and visit our Colorado page for statewide context.
Drinking water is one exposure route. These federal datasets also cover Douglas County, CO.
The EPA places Douglas 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.
8% of homes in Douglas County, CO were built before 1980, and 1% 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 Douglas County, CO averages 5.5 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