Tap Water Quality Report
Tap water quality in Denver, Colorado
Tap water in Denver, Colorado receives a grade of D (66/100) from TapWaterSafety.org. It's served by Denver Municipal Water System. The most significant water quality concerns are: Lead detected in source water; Haloacetic Acids (HAA5) significantly above health guideline; Chromium-6 detected. Data sources: EPA SDWIS, EPA ECHO, EWG Tap Water Database, and Denver's published Consumer Confidence Report.
What's in Denver's tap water
Top water quality concerns identified by the EPA and Environmental Working Group across the utility serving Denver.
Lead detected in source water
Severe concernLead detected at 1.7 ppb. EWG considers no level of lead safe; EPA's action level is 15 ppb.
Haloacetic Acids (HAA5) significantly above health guideline
Moderate concernHaloacetic Acids (HAA5) detected at 27.1 ppb, 271x above the EWG health guideline of 0.1 ppb.
Chromium-6 detected
Moderate concernChromium-6 detected at 0.17 ppb.
Recommended filters for Denver
Filters matched to the specific contaminants in Denver's water supply.
NSF/ANSI 53 certified for lead removal
$80-$750NSF 53 is the gold standard certification for lead removal. Required when lead is a documented concern.
Carbon block (NSF/ANSI 42 + 53)
$40-$750Activated carbon is highly effective for disinfection byproducts like TTHM and HAA5.
Reverse Osmosis
$249-$750Chromium-6 requires reverse osmosis for reliable removal. Standard carbon filters do not address it.
Disclosure: TapWaterSafety earns a commission from purchases made through these links. This does not influence our scoring methodology or filter selection.
All contaminants detected in Denver's tap water
Every contaminant identified, compared side-by-side against US EPA legal limits, the EU Drinking Water Directive (2020/2184), WHO Guidelines, and California's Public Health Goal. Why we show multiple standards →
| Contaminant | Detected | EWG US health-based |
EPA US legal |
EU DWD Europe |
WHO global |
CA PHG strictest US |
Tested sample year |
Status |
|---|---|---|---|---|---|---|---|---|
| Haloacetic Acids (HAA5) Disinfection byproduct |
27.1 ppb | 0.1 | 60 | 60 | — | — | 2022 | 271× over |
| Total Trihalomethanes (TTHMs) Disinfection byproduct |
62.6 ppb | 0.6 | 80 | 100 | — | — | 2022 | 104× over |
| Nitrate Inorganic |
1.76 mg/L | 0.14 | 10 | 11.3 | 11.3 | 10 | 2022 | 13× over |
| Chromium-6 (Hexavalent) Heavy metal |
0.194 ppb | 0.02 | — | — | — | 0.02 | 2022 | 9.7× over |
| Lead Heavy metal |
2.09 ppb | 0 | 15 | 5 | 10 | 0.2 | 2022 | — |
All values in the unit of the detected level. Red cells indicate the detected level exceeds that standard. Some contaminants have limits in some jurisdictions but not others (shown as —). The "Tested" column shows the year each contaminant sample was collected.
Sources: US EPA, EU Drinking Water Directive 2020/2184, WHO Guidelines, California OEHHA PHGs, EWG Tap Water Database.
Treatment plant contact info
For service issues, water quality concerns, or to request a Consumer Confidence Report from Denver Municipal Water System.
General Contact
Water Quality Contact
For questions about contaminants or test results.