What Denver Residents Should Know
Denver's drinking water comes primarily from snowmelt collected from mountain watersheds in the South Platte River, Fraser River, and Blue River in the Colorado River Basin. Denver Water, which serves approximately 1.5 million people in the Denver metro area, collects this high-quality source water in a network of reservoirs that provide year-round supply to the Mile High City.
While the source water is generally of excellent quality, Denver faces several significant water quality challenges. The city's long history has left a legacy of lead service lines and plumbing components in homes built before 1986, particularly in older neighborhoods. This is compounded by the natural corrosivity of Denver's water, which is soft (low in dissolved minerals) and can leach lead from these older pipes.
In response to these challenges, Denver Water implemented a comprehensive Lead Reduction Program in 2020, including adjusting the water's pH and adding orthophosphate to reduce corrosion, free filter distribution to at-risk households, and an ambitious plan to replace all lead service lines within 15 years. Additionally, the water system must address challenges related to wildfire impacts, historic mining contaminants, and the effects of prolonged drought on water quality.
Key Contaminants Found
These substances have been detected in Denver's water supply at levels that may be concerning for some residents.
Lead
Near Limit in Some AreasSource: Lead service lines, lead solder in plumbing, and older fixtures in pre-1986 buildings
Health Effects: Developmental delays in children, learning disabilities, reduced IQ, kidney problems, high blood pressure
Denver Levels: Average 6.1 ppb (90th percentile), with approximately 7% of samples exceeding the EPA action level
EPA Limit: Action level 15 ppb, but no safe level exists
Heavy Metals (Legacy Mining)
Below Limit, But PresentSource: Historical mining activity in mountain watersheds, particularly in the South Platte Basin
Health Effects: Varies by metal; can include nervous system damage, kidney issues, developmental problems
Denver Levels: Below EPA limits but present; primarily cadmium, arsenic, and uranium in trace amounts
EPA Limit: Varies by metal; all currently below regulatory limits
Total Trihalomethanes (TTHMs)
Below LimitSource: Byproducts formed when chlorine used to disinfect water reacts with organic matter
Health Effects: Potential increased risk of cancer with long-term exposure, liver and kidney problems
Denver Levels: 35-45 ppb, varying by location and season
EPA Limit: 80 ppb
Soft Water Minerals
Not a Health ConcernSource: Natural mineral content from mountain watersheds
Health Effects: No direct health concerns; Denver's slightly soft water requires pH adjustment to prevent pipe corrosion
Denver Levels: 3.6 grains per gallon (61.5 mg/L), considered "moderately soft"
EPA Limit: Not regulated (aesthetic characteristic only)
Neighborhood Variations
Water quality can vary significantly across Denver's diverse neighborhoods, primarily due to differences in building age and infrastructure.
Water Quality by Area
| Neighborhood/Area | Risk Level | Treatment Plant | Buildings Pre-1986 | Notable Concerns |
|---|---|---|---|---|
| Baker/West Washington Park | High | Marston | 85% | Lead, Aging Infrastructure |
| Five Points/Cole | High | Foothills | 82% | Lead, Aging Infrastructure |
| Highland/Berkeley | Medium | Moffat | 75% | Lead, TTHMs |
| Capitol Hill/Cheesman Park | Medium | Foothills | 72% | Lead, TTHMs |
| Cherry Creek/Washington Park | Medium | Marston | 65% | Lead, Legacy Mining Contaminants |
| Stapleton/Lowry | Low | Moffat | 25% | Minimal Concerns |
Data based on Denver Water sampling and building age estimates.
Recommended Action Steps
Based on Denver's water quality data, we recommend these actions to protect yourself and your family.
Check If You Qualify for Denver Water's Filter Program
Denver Water provides free water pitchers, filters, and replacement cartridges to homes with suspected lead service lines or plumbing. Check if your home is in the program area and register to receive these free resources.
Filter Program InformationUse Cold Water for Consumption
Always use cold water for drinking, cooking, and preparing baby formula. Hot water can contain higher levels of lead and other contaminants as it dissolves them more readily from pipes. Run cold water for 1-2 minutes before using it, especially first thing in the morning.
Check Your Service Line Material
Denver Water is documenting lead service lines throughout the city. Use their online tool to determine if your property has a lead service line, and learn about the replacement program that aims to replace all lead service lines within the next 15 years at no direct cost to customers.
Lead Service Line InformationClean Faucet Aerators Regularly
Particles containing lead can sometimes get caught in the mesh screens of faucet aerators, especially after plumbing work. Clean these screens regularly (every few months) by unscrewing the aerator and rinsing out any debris.
Test Your Water
If you have concerns about your water quality, particularly if you live in an older neighborhood, request a water quality test from Denver Water. They offer free lead testing for customers in high-risk areas.
Water Quality TestingStay Informed About Drought Impacts
Colorado's ongoing drought conditions can affect water quality by concentrating contaminants in reservoirs and rivers. Stay informed about Denver Water's communications regarding drought conditions and any resulting water quality advisories.
Drought InformationWant to know your personal water quality risk?
Answer a few quick questions about your home and get a personalized water quality assessment and action plan.
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