Drinking water quality · 2023
· Verified
What's in Denver, CO tap water
16 contaminants were measured in the Denver, CO water system's 2023 annual report. Each is shown below against its federal limit — 5 sit at or above that limit.
- Reporting year
- 2023
- Contaminants measured
- 16
- Over federal limit
- 5
- Approaching the limit
- 0
- Worst contaminant
- Fluoride
- Service area
- CO
- FluorideInorganic chemicals · Average618 ug/Llimit 4 ug/L · 154.5× the limit
- CopperMetals · 90th percentile60 ug/Llimit 1 ug/L · 60.0× the limit
- BariumMetals · Average41.3 ug/Llimit 2 ug/L · 20.6× the limit
- NitrateInorganic chemicals · Average91 ug/Llimit 10 ug/L · 9.1× the limit
- LithiumMetals · Average9.23 ug/Llimit 9 ug/L · 1.0× the limit
PFAS — EPA UCMR5 (2023–2025)
1 PFAS compound detected in Denver, CO
The EPA finalized the first-ever federal drinking-water limits for six PFAS compounds in April 2024. These numbers come straight from EPA's UCMR5 lab dataset — every U.S. system serving more than 3,300 people tested every PFAS sample at an entry point to its distribution system. PFAS not listed below were either tested and not detected, or not yet sampled.
Lithium
● Detected (no federal limit)below national p90 (76.59999999999991 mg/L across detecting U.S. systems)
Where your water comes from · EPA SDWIS
Denver, CO's drinking water comes from surface water, drawn from 4 sources.
Source
- MARSTON FOREBAY
- RALSTON RESERVOIR INTAKE
- S PLATTE DIVERSION CONDUIT
- STRONTIA SPRINGS RES INTAKE
Treatment
- FOOTHILLS WTP
- MARSTON WTP
- MOFFAT WTP
- + 2 more
Distribution
Historical readings · EPA Six-Year Review (2012–2019)
30 historically-detected contaminants in Denver, CO
Every U.S. public water system reports compliance-monitoring data to EPA. The Six-Year Review releases the 2012–2019 window as a single dataset — here's what your system reported, year by year. Values shown are the highest detection per analyte per year, compared to the federal MCL.
| Contaminant | Worst detection | EPA limit | Years (2012–2019) |
|---|---|---|---|
GROSS BETA worst: 2013 | 3 mrem/yr within | 4 mrem/yr | '13'15 |
HAA5 worst: 2013 | 0.038 mg/L within | 0.06 mg/L | '12'13'14'15'16'17'18'19 |
TTHM worst: 2015 | 0.0416 mg/L within | 0.08 mg/L | '12'13'14'15'16'17'18'19 |
RADIUM 226 228 worst: 2013 | 2 pCi/L within below national p90 | 5 pCi/L | '13'14 |
FLUORIDE worst: 2016 | 1.08 mg/L within | 4 mg/L | '12'13'14'15'16'17'18'19 |
SELENIUM worst: 2017 | 0.0068 mg/L within | 0.05 mg/L | '17'18 |
GROSS ALPHA worst: 2012 | 2 pCi/L within | 15 pCi/L | '12'13 |
CYANIDE worst: 2012 | 0.025 mg/L within below national p90 | 0.2 mg/L | '12 |
ARSENIC worst: 2017 | 0.0012 mg/L within below national p90 | 0.01 mg/L | '17 |
CARBON TETRACHLORIDE worst: 2012 | 0.0005 mg/L within below national p90 | 0.005 mg/L | '12'13 |
NITRATE worst: 2013 | 0.66 mg/L within | 10 mg/L | '12'13'14'15'16'17'18'19 |
ANTIMONY worst: 2017 | 0.00028 mg/L within below national p90 | 0.006 mg/L | '15'16'17'18 |
CHROMIUM worst: 2013 | 0.004 mg/L within below national p90 | 0.1 mg/L | '13'16'17'18 |
MERCURY worst: 2018 | 0.00007 mg/L within | 0.002 mg/L | '18 |
THALLIUM worst: 2017 | 0.00006 mg/L within | 0.002 mg/L | '17 |
NITRATE NITRITE worst: 2013 | 0.29 mg/L within | 10 mg/L | '12'13'14'15'19 |
BARIUM worst: 2019 | 0.05 mg/L within below national p90 | 2 mg/L | '12'13'14'15'16'17'18'19 |
CADMIUM worst: 2018 | 0.0001 mg/L within below national p90 | 0.005 mg/L | '17'18 |
BERYLLIUM worst: 2017 | 0.00006 mg/L within below national p90 | 0.004 mg/L | '17 |
TWOFOURD worst: 2017 | 0.0001 mg/L within below national p90 | 0.07 mg/L | '17 |
URANIUM worst: 2013 | 0.0063 ug/L within below national p90 | 30 ug/L | '13'14'15'16'17 |
DBAA worst: 2016 | 0.0014 mg/L | — | '16'17'18'19 |
DCAA worst: 2016 | 0.0177 mg/L | — | '16'17'18'19 |
MBAA worst: 2016 | 0.001 mg/L | — | '16'17'18'19 |
MCAA worst: 2016 | 0.0021 mg/L | — | '16'17'18 |
TCAA worst: 2016 | 0.0087 mg/L | — | '16'17'18'19 |
BROMODICHLOROMETHANE worst: 2012 | 0.0098 mg/L | — | '12'13'14'15'16'17'18'19 |
BROMOFORM worst: 2012 | 0.0006 mg/L | — | '12'13'16'17'18'19 |
CHLOROFORM worst: 2012 | 0.0146 mg/L | — | '12'13'14'15'16'17'18'19 |
DIBROMOCHLOROMETHANE worst: 2012 | 0.0047 mg/L | — | '12'13'14'15'16'17'18'19 |
Metals
| Contaminant | Measured | Federal limit | Status |
|---|---|---|---|
| CopperA metal that enters water from corroding household plumbing. | 60 ug/L90th percentileAt the tap | 1 ug/LAction level | At or above the limit |
| LeadA toxic metal that leaches into water from old service lines, solder, and plumbing fixtures. | 3.9 ug/L90th percentileAt the tap | 15 ug/LAction level | Within the limit |
| NickelA metal from natural deposits and industrial discharge. | 0.94 ug/LAverageSystem-wide | None set | Detected — no federal limit |
| SodiumA naturally occurring salt component. | 24000 ug/LAverageSystem-wide | None set | Detected — no federal limit |
Radionuclides
| Contaminant | Measured | Federal limit | Status |
|---|---|---|---|
| Combined RadiumCombined radium-226 and radium-228 — naturally occurring radioactive elements. | 1.1 pCi/LAverageSystem-wide | 5 pCi/LMCL | Within the limit |
Disinfectants
| Contaminant | Measured | Federal limit | Status |
|---|---|---|---|
| ChlorineA disinfectant added to drinking water to kill bacteria and viruses. | 0.2Reported levelSystem-wide | 4MRDL | Within the limit |
Microbial
| Contaminant | Measured | Federal limit | Status |
|---|---|---|---|
| Total ColiformA group of bacteria used as an indicator of overall water-system sanitation. | 2Reported levelNumber of Positives | 0MCLG | Detected — no federal limit |
Physical & aggregate
| Contaminant | Measured | Federal limit | Status |
|---|---|---|---|
| TurbidityA measure of cloudiness from suspended particles in the water. | 0.203 NTUReported levelSystem-wide | None set | Detected — no federal limit |
People also ask about Denver, CO's water
+Is Denver, CO tap water safe to drink in 2023?
The 2023 Consumer Confidence Report for the Denver, CO water utility lists 5 contaminants at or above the federal limit: Fluoride, Copper, Barium, Nitrate, and Lithium. Whether that means the water is "unsafe" depends on which contaminant, how long the exposure, and individual health factors. The table on this page shows the measured value, the federal threshold, and the regulated statistic used for compliance.
+What contaminants are in Denver, CO tap water?
16 contaminants were measured in Denver, CO's 2023 Consumer Confidence Report, spanning metals, radionuclides, and disinfection byproducts. 13 have an enforceable federal limit; the rest are detected but unregulated. Every measured value, in the utility's own units, is on this page.
+Which contaminants exceed federal limits in Denver, CO tap water?
5 contaminants in Denver, CO's 2023 report sit at or above the federal limit: Fluoride (154.5× the limit); Copper (60.0× the limit); Barium (20.6× the limit); Nitrate (9.1× the limit); Lithium (1.0× the limit). The EPA enforces these limits against the regulated reporting statistic — typically a running annual average or 90th percentile — not a one-off sample spike.
+What is the worst contaminant in Denver, CO tap water?
The contaminant with the highest measured value relative to its federal limit in the 2023 report is Fluoride, at 154.5× the federal threshold. It belongs to the inorganic chemicals family of contaminants.
+Where does the data on this page come from?
Every value is transcribed from Denver, CO's 2023 Consumer Confidence Report — the annual drinking-water report every U.S. public water utility is required by federal law to publish. The original source document is archived and viewable on this site. A water-quality report covers an entire service area, not a single address.
+How often is Denver, CO's water quality data updated?
Each U.S. public water utility publishes one Consumer Confidence Report per year, covering the prior calendar year's measurements. This page reflects the 2023 report; a new report will replace it once the utility publishes its next annual update.