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Denver, CO · 1,360,008 people served · EPA data 2021–2026

Tap water quality in Denver, Colorado

Denver's water systems logged 1 health-based EPA violation in 2021–2026, most recently in 2021 — a modest record, with surface water treatment rule the issue found. For context, Colorado's systems average 2.2 health-based violations each.

B-Good
Denver water grade: B-
Good — our A–F grade from this city's EPA compliance record, relative to Colorado and the nation. How we grade →
Health-based violations, 2021–20261
Surface Water Treatment Rule1
Denver Water Board1,287,000 served
Crestview Wsd23,756 served
Cherry Creek Valley Wsd22,000 served
North Washington Street Wsd14,500 served
Colorado quality rank#13 / 51 (86.7/100)
Colorado avg hardness185 PPM (very hard)
Want to know what's actually in your Denver water?

Averages describe states, not your faucet. A certified home water test screens for lead, nitrates, bacteria and dozens of other contaminants — the same categories EPA regulates.

Test your water at home

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Denver tap water FAQ

Is tap water safe to drink in Denver?

Denver's systems logged 1 health-based violation in 2021–2026, most commonly surface water treatment rule. A violation is a red flag for a period of time, not a permanent condition — your utility's current Consumer Confidence Report shows today's status, and a certified home test shows what's at your tap.

Who supplies Denver's water?

Denver Water Board (serving about 1,287,000 people); Crestview Wsd (serving about 23,756 people); Cherry Creek Valley Wsd (serving about 22,000 people); North Washington Street Wsd (serving about 14,500 people). Data: EPA Safe Drinking Water Information System, July 2026.

How hard is the water in Denver?

City-level hardness isn't published in a single federal dataset, but Colorado averages 185 PPM — "very hard" on the USGS scale. Your utility's water quality report lists Denver's exact hardness, or a $10 test strip tells you in a minute. If it comes back over 120 PPM, see our water softener guidance in the purification calculator.

Do I need a water filter in Denver?

With 1 health-based violation on record in 2021–2026, a certified filter is reasonable insurance here: reverse osmosis ($150–$1,300 installed, Angi 2026) covers lead, nitrates and PFAS at the tap. Test first ($50–$200) so you buy for what's actually present.

Want to know what's actually in your Denver water?

Averages describe states, not your faucet. A certified home water test screens for lead, nitrates, bacteria and dozens of other contaminants — the same categories EPA regulates.

Test your water at home

We may earn a commission if you request quotes through this link. It costs you nothing and never affects the data we publish.