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Not health advice. Contact your local water utility for concerns.
Data from EPA Water Quality Reports. For official information, contact your water utility or health department.
EPA records for DENVER WATER BOARD • Updated September 2026
Grade A — based on EPA compliance records, lead testing and PFAS monitoring
DENVER WATER BOARD has a clean recent record: no health-based violations in the last five years and no lead, PFAS or historical monitoring result that costs it more than a few points.
Yes — by EPA's records Denver, CO tap water is safe to drink and earns an A. The grade rests on no health-based EPA violations in the last five years and lead at 3.1 ppb (90th percentile, 2025) against the 15 ppb action level. Lead from your own service line or plumbing is the main risk city-level data cannot see, so homes built before 1986 should still test at the tap.
Yes — by EPA's records Denver, CO tap water is safe to drink and earns an A. The grade rests on no health-based EPA violations in the last five years and lead at 3.1 ppb (90th percentile, 2025) against the 15 ppb action level. Lead from your own service line or plumbing is the main risk city-level data cannot see, so homes built before 1986 should still test at the tap.
DENVER WATER BOARD's most recent Lead and Copper Rule result (2025-07-01 to 2025-12-31) was 3.1 ppb at the 90th percentile, below EPA's 15 ppb action level. Because lead usually comes from service lines and household plumbing, homes built before 1986 should still test at the tap.
No. None of the 435 UCMR5 PFAS results for DENVER WATER BOARD (2023-03-06 to 2025-04-21) were at or above the reporting limit of roughly 3–5 ppt.
DENVER WATER BOARD has 35 violations on file since 2016: 0 health-based in the last five years and 34 monitoring or reporting violations in that window. Monitoring violations are paperwork lapses, not measured contamination.
DENVER WATER BOARD reports surface water as its primary source and serves about 1,287,000 people (EPA PWSID CO0116001).
Not on the strength of EPA's data for DENVER WATER BOARD. A filter still helps with taste and with lead from your own plumbing, which no city-level test can measure.
Want to know what's really in your Denver tap water?
EPA data describes water leaving the plant — a certified mail-in lab test shows what reaches your own faucet, including lead from household plumbing.
Tap Score certified lab · Amazon. We may earn a commission, at no extra cost to you.
DENVER WATER BOARD · SDWIS records since 2016 · 5-year window starts 2021-09-07
EPA records no health-based violations for this system in the last five years. The 34 violations on file in that window are monitoring or reporting paperwork issues, not measured contaminant exceedances.
| Violation | Category | Compliance period | Status |
|---|---|---|---|
| Monitoring, Turbidity (Enhanced SWTR)Interim Enhanced Surface Water Treatment Rule | Monitoring & reporting | 2024-03-01 → 2024-03-31 | Resolvedreturned 2024-03-31 |
| Monitoring, RegularCombined Uranium | Monitoring & reporting | 2024-01-01 → 2024-03-31 | Resolvedreturned 2024-03-31 |
| Monitoring, RegularMethoxychlor | Monitoring & reporting | 2023-01-01 → 2025-12-31 | Archived |
| Monitoring, RegularToxaphene | Monitoring & reporting | 2023-01-01 → 2025-12-31 | Archived |
| Monitoring, RegularDiquat | Monitoring & reporting | 2023-01-01 → 2025-12-31 | Archived |
| Monitoring, RegularDalapon | Monitoring & reporting | 2023-01-01 → 2025-12-31 | Archived |
| Monitoring, RegularOXAMYL | Monitoring & reporting | 2023-01-01 → 2025-12-31 | Archived |
| Monitoring, RegularDi(2-ethylhexyl) phthalate | Monitoring & reporting | 2023-01-01 → 2025-12-31 | Archived |
| Monitoring, RegularDinoseb | Monitoring & reporting | 2023-01-01 → 2025-12-31 | Archived |
| Monitoring, RegularHexachlorocyclopentadiene | Monitoring & reporting | 2023-01-01 → 2025-12-31 | Archived |
| Monitoring, RegularAldicarb sulfone | Monitoring & reporting | 2023-01-01 → 2025-12-31 | Archived |
| Monitoring, RegularCarbofuran | Monitoring & reporting | 2023-01-01 → 2025-12-31 | Archived |
| Monitoring, RegularAtrazine | Monitoring & reporting | 2023-01-01 → 2025-12-31 | Archived |
| Monitoring, RegularHeptachlor epoxide | Monitoring & reporting | 2023-01-01 → 2025-12-31 | Archived |
| Monitoring, Regular2,4-D | Monitoring & reporting | 2023-01-01 → 2025-12-31 | Archived |
| Monitoring, Regular2,4,5-TP | Monitoring & reporting | 2023-01-01 → 2025-12-31 | Archived |
| Monitoring, RegularHEXACHLOROBENZENE | Monitoring & reporting | 2023-01-01 → 2025-12-31 | Archived |
| Monitoring, RegularPentachlorophenol | Monitoring & reporting | 2023-01-01 → 2025-12-31 | Archived |
| Monitoring, RegularPicloram | Monitoring & reporting | 2023-01-01 → 2025-12-31 | Archived |
| Monitoring, RegularDi(2-ethylhexyl) adipate | Monitoring & reporting | 2023-01-01 → 2025-12-31 | Archived |
| Monitoring, RegularBenzo(a)pyrene | Monitoring & reporting | 2023-01-01 → 2025-12-31 | Archived |
| Monitoring, RegularETHYLENE DIBROMIDE | Monitoring & reporting | 2023-01-01 → 2025-12-31 | Archived |
| Monitoring, RegularEndrin | Monitoring & reporting | 2023-01-01 → 2025-12-31 | Archived |
| Monitoring, RegularChlordane | Monitoring & reporting | 2023-01-01 → 2025-12-31 | Archived |
| Monitoring, RegularHeptachlor | Monitoring & reporting | 2023-01-01 → 2025-12-31 | Archived |
Showing 25 of 35 violations on file. Full record on EPA ECHO.
Source: ECHO SDWA bulk download (SDWA_VIOLATIONS_ENFORCEMENT.csv, SDWIS 2026Q2, file dated 2026-07-09, fetched 2026-09-06)
EPA Lead and Copper Rule 90th-percentile results reported by DENVER WATER BOARD
Well below the 15 ppb action level. In the most recent monitoring period on file (2025-07-01 to 2025-12-31), 90% of the homes DENVER WATER BOARD sampled had lead at or below 3.1 ppb.
EPA's action level is 15 ppb (dropping to 10 ppb under the 2024 Lead and Copper Rule Improvements). There is no safe level of lead; the 90th-percentile figure describes the system, not your tap — homes with lead service lines or pre-1986 plumbing can be higher.
| Monitoring period | Lead 90th percentile | vs 15 ppb action level |
|---|---|---|
| 2025-07-01 → 2025-12-31 | 3.1 ppb | Well below the 15 ppb action level |
| 2025-01-01 → 2025-06-30 | 3.9 ppb | Well below the 15 ppb action level |
| 2024-07-01 → 2024-12-31 | 3.6 ppb | Well below the 15 ppb action level |
| 2024-01-01 → 2024-06-30 | 4 ppb | Well below the 15 ppb action level |
| 2023-07-01 → 2023-12-31 | 3.9 ppb | Well below the 15 ppb action level |
| 2023-01-01 → 2023-06-30 | 3.5 ppb | Well below the 15 ppb action level |
| 2022-07-01 → 2022-12-31 | 3.8 ppb | Well below the 15 ppb action level |
| 2022-01-01 → 2022-06-30 | 3.9 ppb | Well below the 15 ppb action level |
| 2021-07-01 → 2021-12-31 | 4.5 ppb | Well below the 15 ppb action level |
| 2021-01-01 → 2021-06-30 | 4.1 ppb | Well below the 15 ppb action level |
| 2020-07-01 → 2020-12-31 | 4.1 ppb | Well below the 15 ppb action level |
| 2020-01-01 → 2020-06-30 | 6.7 ppb | Below the action level, but detectable |
Source: ECHO SDWA bulk download (SDWA_LCR_SAMPLES.csv, SDWIS 2026Q2, file dated 2026-07-09, fetched 2026-09-06)
EPA UCMR5 monitoring, 2023-03-06 to 2025-04-21 · 435 PFAS results at entry points to the distribution system
No PFAS detected. None of the 435 UCMR5 PFAS results for DENVER WATER BOARD were at or above the method reporting limit. Reporting limits are about 3–5 ppt, so “not detected” means below that threshold — not proven zero.
| Compound | Detects / samples | Max (ppt) | Reporting limit | EPA MCL |
|---|---|---|---|---|
| PFOA | 0 / 15 | < 4 | 4 ppt | 4 ppt |
| PFOS | 0 / 15 | < 4 | 4 ppt | 4 ppt |
| PFHxS | 0 / 15 | < 3 | 3 ppt | 10 ppt |
| PFNA | 0 / 15 | < 4 | 4 ppt | 10 ppt |
| HFPO-DA | 0 / 15 | < 5 | 5 ppt | 10 ppt |
| PFBS | 0 / 15 | < 3 | 3 ppt | hazard index only |
“< 4 ppt” means below the laboratory reporting limit, not zero. ppt = parts per trillion (ng/L). Results are for finished water leaving the treatment plant.
Lithium (also monitored under UCMR5, not a PFAS): detected in 5 of 15 samples, max 10.8 µg/L. There is no federal limit for lithium.
What PFAS are and how to remove them →
Source: UCMR5 occurrence data, EPA Data Summary July 2026 (UCMR5_All.txt)
EPA Six-Year Review 4 compliance samples for DENVER WATER BOARD · finished water only · dated data, released 2024
These are the regulated-contaminant samples DENVER WATER BOARD reported to its state between 2012 and 2019 — the most recent nationwide sample-level dataset EPA has published. Every scored contaminant stayed within its Maximum Contaminant Level (MCL) and averaged below 80% of the limit. Treat this as history, not today's tap water.
| Contaminant | Samples | Average | Max | EPA limit | Status |
|---|---|---|---|---|---|
| Arsenic | 1814 detects | 0.018 µg/L | 1.2 µg/L | 10 µg/LMCL | Within MCL |
| Nitrate (as N) | 10767 detects | 0.068 mg/L | 0.66 mg/L | 10 mg/LMCL | Within MCL |
| Fluoride | 256255 detects | 0.615 mg/L | 1.08 mg/L | 4 mg/LMCL | Within MCL |
| Chromium (total) | 18131 detects | 0.179 µg/L | 4 µg/L | 100 µg/LMCL | Within MCL |
| Uranium (combined) | 13326 detects | 0.245 µg/L | 6.3 µg/L | 30 µg/LMCL | Within MCL |
| Radium-226/228 | 92 detects | 0.333 pCi/L | 2 pCi/L | 5 pCi/LMCL | Within MCL |
| Gross alpha | 222 detects | 0.182 pCi/L | 2 pCi/L | 15 pCi/LMCL | Within MCL |
| Total trihalomethanes (TTHM) | 1,166 | 23.023 µg/L | 41.64 µg/L | 80 µg/LMCL (LRAA) | Within MCL |
| Haloacetic acids (HAA5) | 1,1641135 detects | 13.742 µg/L | 38 µg/L | 60 µg/LMCL (LRAA) | Within MCL |
Averages count non-detects as zero. TTHM and HAA5 limits are locational running annual averages, so a single high sample is not a violation — we grade those on the average only. Lead and copper rows are individual tap samples and are shown for context; compliance (and our score) uses the 90th-percentile result above. LRAA = locational running annual average; ND = not detected.
Source: SYR4 Six-Year Review compliance monitoring data 2012–2019 (released 2024-03)
DENVER WATER BOARD · 311,392 service lines inventoried · Q2 2026 snapshot
DENVER WATER BOARD reports 16,674 service lines that are lead or galvanized-requiring-replacement (5.4% of the lines it has inventoried), plus 34,057 lines whose material is still unknown. A lead service line is the pipe between the water main and a building, so treated water can pick up lead after it leaves the plant — which city-level testing does not capture. Under EPA's Lead and Copper Rule Improvements, utilities must replace lead lines within 10 years starting in 2027.
Source: EPA SDWIS Service Line Inventory (Q2 2026) · PWS ID CO0116001 · See all Colorado lead service lines. We may earn a commission from filters and test kits, at no extra cost to you.
Surface-water systems draw from rivers, lakes or reservoirs and must filter and disinfect, which is why disinfection byproducts (TTHM, HAA5) are the readings to watch.
How to test your tap water and the treatment options that actually fit Denver homes
The most reliable way to know what is actually coming out of your tap is a certified mail-in lab test. City-wide EPA data (like the report above) reflects the water leaving the treatment plant, but contaminants such as lead and copper can be picked up from your own service line and household plumbing — so the water at your Denver faucet can differ from the system average. A state-certified lab measures dozens of contaminants at once with results you can trust; you can also find one near you through the EPA's certified-lab list at epa.gov/dwlabcert. Hardware-store test strips are cheaper and instant, but they only screen for a few basics (chlorine, hardness, pH, and a rough lead pass/fail) and are far less accurate — treat them as a first look, not a diagnosis.
Match the treatment to what your test finds. Reverse osmosis (RO) removes the widest range of contaminants — lead, arsenic, nitrate, PFAS, and dissolved solids — which makes an under-sink reverse osmosis system the most thorough choice for Denver households with heavy-metal or PFAS concerns. If your main issue is taste, odor, or chlorine, an activated carbon filter (pitcher, faucet, or under-sink) is simpler and cheaper and handles chlorine and many organic compounds well, though carbon alone does not remove arsenic, nitrate, or most PFAS. NSF-certified pitchers rated for lead reduction are the easiest way to start today while you decide on a permanent setup.
We may earn a commission from testing kits and filters purchased through these links, at no extra cost to you.
What Denver residents measured at their own tap (ZIPs 80123, 80202, 80203, 80204 +30 more). All reader results →
Reader submissions are unverified and shown separately from EPA data. They reflect one tap on one day, not the utility's compliance record.
No reader results for Denver yet - yours would be the first. A hardness or TDS number from a $10 strip kit is enough to start the map.
Help build the first reader-sourced water map. Enter whatever your test strip, TDS pen or lab report shows - one number is enough.
Denver ranks #29 of 35 graded Colorado cities.
Yes — by EPA's records Denver, CO tap water is safe to drink and earns an A. The grade rests on no health-based EPA violations in the last five years and lead at 3.1 ppb (90th percentile, 2025) against the 15 ppb action level. Lead from your own service line or plumbing is the main risk city-level data cannot see, so homes built before 1986 should still test at the tap.
DENVER WATER BOARD's most recent Lead and Copper Rule result (2025-07-01 to 2025-12-31) was 3.1 ppb at the 90th percentile, below EPA's 15 ppb action level. Because lead usually comes from service lines and household plumbing, homes built before 1986 should still test at the tap.
No. None of the 435 UCMR5 PFAS results for DENVER WATER BOARD (2023-03-06 to 2025-04-21) were at or above the reporting limit of roughly 3–5 ppt.
DENVER WATER BOARD has 35 violations on file since 2016: 0 health-based in the last five years and 34 monitoring or reporting violations in that window. Monitoring violations are paperwork lapses, not measured contamination.
DENVER WATER BOARD reports surface water as its primary source and serves about 1,287,000 people (EPA PWSID CO0116001).
Not on the strength of EPA's data for DENVER WATER BOARD. A filter still helps with taste and with lead from your own plumbing, which no city-level test can measure.
Even with good water quality, a filter removes trace contaminants and improves taste.
For Everyday Peace of Mind
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Your water already tests well — a simple carbon filter improves taste and catches trace contaminants.
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Tap water is one piece of the picture — our sister sites cover the rest for Denver, CO.
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