Green Mountain WSD

Where does your water originate? Denver's municipal water comes from rivers, lakes, streams, reservoirs and springs fed by pristine mountain snowmelt. Denver Water's supply consists entirely of surface water sourced from a watershed spanning 4,000 square miles on both sides of the Continental Divide.

Mountain Water Sources
Denver Water draws from the South Platte River and its tributaries, streams feeding Dillon Reservoir, and waterways above the Fraser River. Water is stored in five mountain reservoirs — Antero, Eleven Mile Canyon, Cheesman, Dillon, and Gross. From these locations, water travels to one of three treatment facilities via an intricate network of waterways, canals, and pipelines.

After treatment, municipal water moves through gravity and pump systems to underground clean-water storage before reaching homes and businesses through more than 3,000 miles of distribution pipes.

Source Water Assessment
State health officials have evaluated potential contamination risks to Denver Water's three terminal reservoirs at Strontia Springs, Marston, and Ralston. Potential contamination sources include: EPA Areas of Concern, Permitted Wastewater Discharge Sites, Storage Tank Locations (above/underground/leaking), Solid Waste Facilities, Mine Sites, Commercial/Industrial/Transportation operations, Residential areas, Recreational Spaces, Quarries, Agricultural land, Forests, Septic Systems, Oil/Gas Wells and Roadways.

Water Quality Commitment
Denver Water proudly serves premium water to 1.4 million residents in Denver and surrounding suburbs. Since 1918, we've expertly developed and managed a sophisticated system delivering clean, safe, great-tasting water. Our public agency is funded through water rates and tap fees rather than taxes. Though we serve 25% of Colorado's population, we use less than 2% of the state's total water supply.

We prioritize environmental stewardship by promoting responsible water usage. Quality assurance is paramount—last year alone, we collected over 35,000 samples and conducted more than 68,000 tests to ensure water safety and purity. Denver Water vigilantly protects mountain water supplies, with careful treatment before delivery to customers.

The Treatment Process
Our water treatment includes five critical steps:

1. COAGULATION/FLOCCULATION — Raw water from terminal reservoirs enters mixing basins where alum and polymer are added, causing small particles to combine into larger, filterable particles.
2. SEDIMENTATION — The larger particles become heavy enough to settle at the basin bottom for removal.
3. FILTRATION — Water passes through layers of fine, granulated materials (sand or sand/coal combination), removing smaller suspended particles and reducing cloudiness.
4. DISINFECTION — Disinfectants protect against remaining bacteria, viruses and microbes before water enters the distribution network. Fluoride occurs naturally but may be supplemented when needed.
5. CORROSION CONTROL — Alkaline materials maintain proper pH levels to minimize corrosion in distribution systems and household plumbing.

All municipal water, including bottled varieties, may contain trace amounts of some contaminants. This doesn't necessarily indicate health risks. For more information about contaminants and potential health effects, contact the EPA Safe Drinking Water Hotline (1-800-426-4791) or visit http://water.EPA.gov/drink/contaminants.

Special Health Considerations
Certain individuals may be more vulnerable to water contaminants than the general population. Those with compromised immune systems—including cancer patients undergoing chemotherapy, organ transplant recipients, people with HIV/AIDS or other immune disorders, some elderly individuals, and infants—may face increased infection risks. These individuals should seek advice from healthcare providers about municipal water consumption.

Lead in Municipal Water
Since 1992, Denver Water has tested high-risk homes for lead and copper contamination per EPA guidelines. The source water, treated water leaving plants, and water in the distribution system contain no detectable lead and only trace copper levels. Lead typically enters water through lead-containing household or building plumbing components.

Homes built before 1950 may have lead service lines connecting street water mains to residences. Properties constructed before 1988 might contain lead solder in their plumbing (banned that year). Homes outside these categories have lower lead contamination risk. Softened water can be more corrosive to household plumbing systems.

Lead exposure poses serious health risks, particularly for pregnant women and young children. To minimize potential exposure after water has been sitting for several hours, flush your cold water tap for up to three minutes before using water for drinking or cooking. Always start with cold water—using hot water directly from the tap isn't recommended as hot water tank environments can be corrosive.

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