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Not health advice. Contact your local water utility for concerns.
Data from EPA Water Quality Reports. For official information, contact your water utility or health department.
Comprehensive water safety analysis • Updated April 2026
Denver's water quality score of 74/100 indicates fair quality with several contaminants worth monitoring.
•All 1 historical violation(s) in Denver have been resolved.
Some Concerns. Consider a water filter for extra protection. Score: 74/100.
Want to understand your score better? Learn how scores are calculated →
8 contaminants tested • EPA SDWIS data • Click any contaminant for details
| Contaminant | Level Detected | EPA Limit | % of Limit | Status |
|---|---|---|---|---|
| Total Trihalomethanes | 27.10 ug/L | 80.00 ug/L | 33.9% | Safe |
| Nitrite | 0.249 mg/L | 1.00 mg/L | 24.9% | Safe |
| Mercury | 0.0004 mg/L | 0.0020 mg/L | 20.7% | Safe |
| Haloacetic Acids | 11.37 ug/L | 60.00 ug/L | 18.9% | Safe |
| Fluoride | 0.647 mg/L | 4.00 mg/L | 16.2% | Safe |
| Arsenic | 0.0015 mg/L | 0.010 mg/L | 15.0% | Safe |
| Lead | 0.0011 mg/L | 0.015 mg/L | 7.3% | Safe |
| Copper | 0.024 mg/L | 1.30 mg/L | 1.9% | Safe |
In-depth assessment of your municipal water supply
The water quality in Denver, Colorado has been comprehensively evaluated using data from the EPA's Safe Drinking Water Information System (SDWIS) and local water utility reports. Our analysis examines 8 distinct contaminants across multiple categories including inorganic chemicals, disinfection byproducts, microorganisms, and radionuclides. With an overall quality score of 74 out of 100 (Grade: B-), Denver's water supply meets minimum EPA requirements but shows areas for improvement.
Denver's primary water system, DENVER WATER SYSTEM, serves approximately 717,347 residents. The water is sourced from surface water sources such as rivers, lakes, or reservoirs. Surface water typically requires more extensive treatment including coagulation, sedimentation, filtration, and disinfection to remove sediments, organic matter, and pathogens.
Of the 8 contaminants analyzed in Denver's water supply, 8 (100%) are present at safe levels below 50% of EPA Maximum Contaminant Levels (MCLs). No contaminants currently exceed EPA safety limits. The most common categories of concern in municipal water supplies include disinfection byproducts formed during the chlorination process, heavy metals like lead that can leach from aging infrastructure, and naturally occurring contaminants like arsenic or radium that vary by geographic region.
Denver's water system has a compliance history with 1 documented EPA violation. All historical violations have been addressed and resolved. Violations can range from monitoring and reporting failures to actual exceedances of contaminant limits. Water utilities are required by law to notify customers of any violations that may affect health and to take corrective action to return to compliance.
Water quality at the tap can differ from quality at the treatment plant due to distribution system conditions. Homes built before 1986 may have lead service lines or lead solder in plumbing that can contribute to lead exposure. Older galvanized pipes can harbor bacteria and release metals. Running cold water for 30 seconds to 2 minutes before drinking or cooking helps flush stagnant water from pipes. Residents in older homes should consider testing their water directly at the tap to assess any additional contamination from household plumbing, as EPA monitoring typically occurs at distribution points rather than individual residences.
Understanding potential health effects for residents
Certain groups face elevated health risks from water contaminants and should take extra precautions. Pregnant women are particularly vulnerable as contaminants like lead and nitrates can affect fetal development, potentially causing developmental delays and birth defects. Infants and young children are at heightened risk because their developing bodies absorb contaminants more readily and are more susceptible to their effects; lead exposure in children can cause irreversible cognitive impairment and behavioral problems. Elderly individuals and those with compromised immune systems (including cancer patients, organ transplant recipients, and HIV/AIDS patients) are more susceptible to waterborne pathogens and may experience severe illness from microorganisms that healthy adults can tolerate. Individuals with kidney disease should be aware of fluoride and other mineral levels, as impaired kidney function affects the body's ability to filter these substances.
Lead has been detected in Denver's water supply. There is no safe level of lead exposure. In children, lead can cause developmental delays, learning difficulties, irritability, weight loss, hearing loss, and seizures. In adults, lead exposure contributes to cardiovascular problems, decreased kidney function, and reproductive issues. Pregnant women exposed to lead can transfer it to their developing fetus, increasing risk of premature birth and reduced growth. Use an NSF 53 certified filter and run cold water before drinking to reduce exposure.
Arsenic has been detected in Denver's water supply. Long-term arsenic exposure, even at levels near EPA limits, is associated with increased risk of skin, lung, bladder, kidney, and liver cancers. Arsenic exposure can also cause cardiovascular disease, diabetes, and neurological effects. Skin changes like thickening and pigmentation may indicate chronic exposure. Reverse osmosis filtration is highly effective at removing arsenic from drinking water.
Based on Denver's water quality profile, residents should consider the following protective measures: A water filter can provide additional protection, particularly for vulnerable household members. Always use cold water for drinking and cooking, as hot water can contain higher levels of metals from pipes. Have your home tested if it was built before 1986 to check for lead plumbing. Review your annual Consumer Confidence Report (water quality report) from your utility to stay informed about local water quality trends. Pregnant women, families with young children, and immunocompromised individuals should consult healthcare providers about water safety precautions specific to their situation.
Based on detected contaminants
Best for Denver. Removes 95-99% of contaminants including heavy metals, PFAS, and nitrates.
Good for Denver. Removes chlorine, improves taste, and filters many organic compounds.
Lead detected in Denver. Ensure any filter is NSF/ANSI 53 certified for lead removal.
Past violations for Denver's water system
monitoring
Lead - 2/4/2022
ResolvedDenver Water Quality Score
Based on EPA contaminant data and compliance records
Even with good water quality, many families choose to filter their water for extra peace of mind.
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Based on contaminants detected in your water, these resources may be helpful:
Explore detailed information about each contaminant detected in Denver's water:
View All Contaminants →Find the right filter for your Denver water quality needs:
Understand the contaminants that may be present in Denver's water supply and their health effects.
Understand your water better with our in-depth guides on contaminants, filtration, and water safety.
Denver's drinking water is managed by DENVER WATER SYSTEM, which serves approximately 717,347 residents through surface water sources such as rivers, lakes, and reservoirs. Our analysis of 8 tested contaminants reveals a quality score of 74/100, placing Denver at a fair level relative to other Colorado communities.
Denver's water quality is strong across all tested parameters, with all contaminants well within EPA safety limits. This reflects effective water treatment and well-maintained infrastructure.
Denver's water system has 1 documented EPA violation in its compliance history. All have since been resolved, indicating the utility has addressed past issues. Compliance history is one of the factors in our scoring methodology.
This report is based on data from the EPA Safe Drinking Water Information System (SDWIS) and the EPA Enforcement and Compliance History Online (ECHO) database. Our scoring algorithm weighs contaminant analysis (50%), compliance history (30%), and infrastructure factors (20%). Data is sourced directly from public EPA records and Consumer Confidence Reports. We are an independent resource with no affiliation to water utilities or government agencies. Learn more about our methodology.
Denver's tap water has some concerns with a quality score of 74/100. We recommend using a water filter for additional protection.
Denver's water has been tested for 8 contaminants. All tested contaminants are within safe limits.
Based on Denver's water quality profile, we recommend a reverse osmosis system for the most comprehensive filtration. View our water filter comparison for recommendations.
Denver's primary water system (DENVER WATER SYSTEM) sources water from surface water such as rivers or reservoirs, serving 717,347 residents.