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Updated 2026-09-16
County water report

Denver County Water Quality

Denver County, Colorado: one city report built from EPA and utility records. A county has many suppliers; each city shows the system that serves it.

Find my systemOpen on the mapPrivate wells in Denver County
Across the county's systems

Highest result for each contaminant

One row per contaminant: the highest result any system in the county reported, against its limit. Open a row for the systems behind it.

LithiumDENVER WATER BOARD10 µg/L EPA health reference level (screening, not a legal limit) · US EPA10.8 µg/L
Total trihalomethanes (TTHM)DENVER WATER BOARD80 ppb federal MCL · US EPA35.5 ppb
Haloacetic acids (HAA5)DENVER WATER BOARD60 ppb federal MCL · US EPA19.5 ppb
Lead (90th percentile)DENVER WATER BOARD15 µg/L federal action level · US EPA3.1 µg/L
FluorideDENVER WATER BOARD4.0 mg/L · US EPA0.61 mg/L
CopperDENVER WATER BOARD1.3 mg/L (action level) · US EPA0.06 mg/L
NitrateDENVER WATER BOARD10 mg/L · US EPA0.1 mg/L
Water hardnessDENVER WATER BOARDAesthetic, no federal health limit · USGS6.1 gpg
29 PFAS tested, none detected in this systemShow

Tested in this system: DENVER WATER BOARD

  • 11-Chloroeicosafluoro-3-oxaundecane-1-sulfonic acid (11Cl-PF3OUdS)
  • 1H, 1H, 2H, 2H-perfluorodecane sulfonic acid (8:2 FTS)
  • 1H, 1H, 2H, 2H-perfluorohexane sulfonic acid (4:2 FTS)
  • 1H, 1H, 2H, 2H-perfluorooctane sulfonic acid (6:2 FTS)
  • 4,8-Dioxa-3H-perfluorononanoic acid (ADONA)
  • 9-Chlorohexadecafluoro-3-oxanone-1-sulfonic acid (9Cl-PF3ONS)
  • Hexafluoropropylene oxide dimer acid (HFPO-DA) (GenX chemicals)
  • N-ethyl perfluorooctanesulfonamidoacetic acid (NEtFOSAA)
  • N-methyl perfluorooctanesulfonamidoacetic acid (NMeFOSAA)
  • Nonafluoro-3,6-dioxaheptanoic acid (NFDHA)
  • Perfluoro (2-ethoxyethane) sulfonic acid (PFEESA)
  • Perfluoro-3-methoxypropanoic acid (PFMPA)
  • Perfluoro-4-methoxybutanoic acid (PFMBA)
  • Perfluorobutanesulfonic acid (PFBS)
  • Perfluorobutanoic acid (PFBA)
  • Perfluorodecanoic acid (PFDA)
  • Perfluorododecanoic acid (PFDoA)
  • Perfluoroheptanesulfonic acid (PFHpS)
  • Perfluoroheptanoic acid (PFHpA)
  • Perfluorohexanesulfonic acid (PFHxS)
  • Perfluorohexanoic acid (PFHxA)
  • Perfluorononanoic acid (PFNA)
  • Perfluorooctanesulfonic acid (PFOS)
  • Perfluorooctanoic acid (PFOA)
  • Perfluoropentanesulfonic acid (PFPeS)
  • Perfluoropentanoic acid (PFPeA)
  • Perfluorotetradecanoic acid (PFTA)
  • Perfluorotridecanoic acid (PFTrDA)
  • Perfluoroundecanoic acid (PFUnA)
1 city

Cities ranked by the records

Showing 1 of 1 cities · scores are system-level, not tap tests

Ranked by the Purity Score of each city's main water system, highest first. Scores belong to water systems; there is no county score. The score is computed only from contaminants measured in the published EPA record, so this ranks the record, not which city's water is safest. How the score works.

PFAS in Denver CountyPFAS detected in 0 of 1 city; none above a federal limit
4.0 ng/L federal MCL · PFOS, ng/LPFAS in Colorado
Lead

0of 1 city above the 15 µg/L action level

Based on each system's 90th-percentile result. Lead from household plumbing isn't in this record.

Lead in Colorado
Hard water

1city reports hardness · Denver, 6.1 gpg

None above 7 gpg, the USGS threshold for hard water. An aesthetic measure with no federal health limit.

Hard water explained
Who supplies the county

Largest water systems

  1. DenverDENVER WATER BOARD · CO0116001
    1,287,000 served
Questions

Frequently asked

How does Denver County tap water compare across cities?

PurityMap ranks 1 city in Denver County by the Purity Score of each city's main water system, computed only from contaminants measured in the published EPA record. Scores belong to water systems, not to cities. The highest published score is Denver's main water system: DENVER WATER BOARD · PWSID CO0116001 · Purity Score 93 (Excellent) · Confidence: high · Assessed at the water-system level. The ranking compares the records, not which city's water is safest, and your own tap can differ with household plumbing.

How many Denver County cities have PFAS above the federal limit?

None of the 1 Denver County cities on record had a regulated PFAS above the 2024 federal limit in EPA's UCMR 5 testing. PFAS were detected below the limit in 0.

Is there lead in Denver County tap water?

Utilities report lead as a 90th-percentile result from home taps. 1 of 1 Denver County cities reported a value above zero, and none was above the 15 µg/L federal action level. Lead usually comes from a building's own pipes and fixtures, so only a test at your tap tells you what you drink.

Does Denver County have hard water?

Hardness is published in utility water-quality reports for 1 Denver County city on record; the hardest is Denver at 6.1 grains per gallon. Hardness affects scale and appliances; it is not a health finding.

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