Tap Water Quality Report
Tap water quality in Denver, Colorado
Tap water in Denver, Colorado receives a grade of C (73/100) from TapWaterSafety.org. It's served by DENVER WATER BOARD. The most significant water quality concerns are: Haloacetic acids (HAA9) significantly above health guideline; Total trihalomethanes (TTHMs) significantly above health guideline; Haloacetic acids (HAA5) significantly above health guideline. Data sources: EPA SDWIS, EPA ECHO, EWG Tap Water Database.
What's in Denver's tap water
Top water quality concerns identified by the EPA and Environmental Working Group across the utility serving Denver.
Haloacetic acids (HAA9) significantly above health guideline
Moderate concernHaloacetic acids (HAA9) detected at 14.7 ppb, 246x above the EWG health guideline of 0.06 ppb.
Total trihalomethanes (TTHMs) significantly above health guideline
Moderate concernTotal trihalomethanes (TTHMs) detected at 28.9 ppb, 192x above the EWG health guideline of 0.15 ppb.
Haloacetic acids (HAA5) significantly above health guideline
Moderate concernHaloacetic acids (HAA5) detected at 16.6 ppb, 166x above the EWG health guideline of 0.1 ppb.
EPA compliance record
Official U.S. EPA records for DENVER WATER BOARD (system ID CO0116001) for the last 3 years. Checked 2026-10-07.
| Rule | Type | Since | Status |
|---|---|---|---|
| Synthetic Organic Chemicals | Missed testing or reporting | 01/01/2023 | Resolved |
| Radionuclides and Revised Rad Rule | Missed testing or reporting | 01/01/2024 | Resolved |
| Interim and Long Term 1 Enhanced Surface Water Treatment Rule | Missed testing or reporting | 03/01/2024 | Resolved |
Source: U.S. EPA Enforcement and Compliance History Online (ECHO), from the Safe Drinking Water Information System. See EPA's full report.
Recommended filters for Denver
Filters matched to the specific contaminants in Denver's water supply.
Carbon filter certified for VOCs (NSF/ANSI 53)
$180-$599Activated carbon is effective for disinfection byproducts. Look for NSF/ANSI 53 VOC reduction.
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 (HAA9) Disinfection byproduct |
14.7 ppb | 0.06 | — | — | — | — | — | 246× over |
| Total trihalomethanes (TTHMs) Disinfection byproduct |
28.9 ppb | 0.15 | 80.0 | 100 | — | — | — | 192× over |
| Haloacetic acids (HAA5) Disinfection byproduct |
16.6 ppb | 0.1 | 60.0 | 60 | — | — | — | 166× over |
| Bromodichloromethane Disinfection byproduct |
8.02 ppb | 0.06 | — | — | — | — | — | 134× over |
| Trichloroacetic acid Disinfection byproduct |
6.33 ppb | 0.1 | — | — | — | — | — | 63× over |
| Dichloroacetic acid Disinfection byproduct |
10.1 ppb | 0.2 | — | — | — | — | — | 51× over |
| Chloroform Disinfection byproduct |
18.9 ppb | 0.4 | — | — | — | — | — | 47× over |
| Dibromochloromethane Disinfection byproduct |
1.9 ppb | 0.1 | — | — | — | — | — | 19× over |
| Radium, combined (-226 and -228) Radiological |
0.74 pCi/L | 0.05 | 5.0 | — | — | — | — | 15× over |
| Dibromoacetic acid Disinfection byproduct |
0.119 ppb | 0.03 | — | — | — | — | — | 4.0× over |
| Chromium (hexavalent) Heavy metal |
0.0378 ppb | 0.02 | — | — | — | — | — | 1.9× over |
| Nitrate Inorganic |
0.0578 ppm | 0.14 | 10.0 | 11.3 | 11.3 | 10 | — | Below guideline |
| Nitrate and nitrite Inorganic |
0.0578 ppm | 0.14 | 10.0 | 11.3 | 11.3 | 10 | — | Below guideline |
| Molybdenum Other |
6.86 ppb | 40.0 | — | — | — | — | — | Below guideline |
| Manganese Heavy metal |
8.41 ppb | 100.0 | — | 50 | 80 | — | — | Below guideline |
| Barium Heavy metal |
34.0 ppb | 700.0 | 2000.0 | — | 1300 | 2000 | — | Below guideline |
| Uranium Radiological |
0.02 pCi/L | 0.43 | 20.0 | 30 | 30 | 0.43 | — | Below guideline |
| Cadmium Heavy metal |
0.00122 ppb | 0.04 | 5.0 | 5 | 3 | 0.04 | — | Below guideline |
| Vanadium Other |
0.264 ppb | 21.0 | — | — | — | — | — | Below guideline |
| Bromoform Disinfection byproduct |
0.00622 ppb | 0.5 | — | — | — | — | — | Below guideline |
| Strontium Radiological |
0.171 ppb | 1500.0 | — | — | — | — | — | Below guideline |
| 4-Androstene-3,17-dione Other |
0.027 ppt | — | — | — | — | — | — | Below guideline |
| Chlorodifluoromethane Other |
0.00808 ppb | — | — | — | — | — | — | Below guideline |
| Chromium (total) Heavy metal |
0.0841 ppb | — | 100.0 | — | — | — | — | Below guideline |
| Fluoride Inorganic |
0.607 ppm | — | 4.0 | 1.5 | 1.5 | — | — | Below guideline |
| Lithium Other |
4.08 ppb | — | — | — | — | — | — | Below guideline |
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 WATER BOARD.
General Contact
Treatment Plant
ZIP codes served
Denver's public water systems serve the following ZIP codes: