Drinking water quality · 2024
· Verified
· PWSID CO0107810
What's in Boulder, CO tap water
4 contaminants in Boulder, CO's water sat at or above a federal limit, led by PFOS at 8.3x the limit.
- !4 contaminants at or above a federal limit — worst is PFOS at 8.3x
- !17 of 27 core regulated contaminants reported — 10 never appear in this report
- ✓No open federal violations
+How this score is calculated
Every system starts at 100. Points come off for measured levels, for the federal violation record, and for how much of the core regulated set the utility actually reported. All three inputs are the utility's own published numbers and EPA's own records.
- −60 contaminants at or above a federal limit
- −0 contaminants within 20% of a limit
- −0 open health-based violations
- −0 open monitoring / reporting violations
- −0 health-based violations resolved in the last 5 years
- −3 core regulated contaminants never reported (17/27)
A 90–100 · B 80–89 · C 70–79 · D 60–69 · F below 60. A system reporting under a third of the core set is capped at C however clean its numbers look — a short report is not a clean bill of health.
Full grading methodology, constant for constant →What to worry about
- PFOS8.3× the federal limit0–33 ng/L · limit 4 ng/L
Linked to cancer, thyroid disease, and immune effects; the EPA set an enforceable limit of 4 parts per trillion.
higher than 95% of U.S. systems
- Perfluorohexanesulfonic acid2.6× the federal limit0–26 ng/L · limit 10 ng/L
Regulated by the EPA at 10 parts per trillion and included in the PFAS Hazard Index.
higher than 90% of U.S. systems
- PFOA2.4× the federal limit9.4 ng/L · limit 4 ng/L
Linked to cancer, liver damage, and immune effects; the EPA set an enforceable limit of 4 parts per trillion.
higher than 85% of U.S. systems
- Chloramine1.2× the federal limit0.2–4.66 mg/L · limit 4 mg/L
Holds disinfection further into the pipe network, but is regulated under the same residual-disinfectant cap as chlorine.
higher than 95% of U.S. systems
+36 contaminants were measured and came in below the limitShow all
| Contaminant | Measured | Federal limit |
|---|---|---|
| Gross Alpha | 0–11.1 pCi/L | 15 pCi/L |
| HAA5 | 32.1 ug/L | 60 ug/L |
| TTHM | 39.7 ug/L | 80 ug/L |
| Chlorite | 0.02–0.426 mg/L | 1 mg/L |
| Selenium | 0–19 ug/L | 50 ug/L |
| Arsenic | 0–3.4 ug/L | 10 ug/L |
| Combined Radium | 0.6–1.4 pCi/L | 5 pCi/L |
| Turbidity | 0.27 NTU | 1 NTU |
| Copper | 0.313 mg/L | 1.3 mg/L |
| Chlorine | 0–956 ug/L | 4000 ug/L |
| Fluoride | 0.5–0.9 mg/L | 4 mg/L |
| Lead | 3 ug/L | 15 ug/L |
| Nitrate | 0–1 mg/L | 10 mg/L |
| Barium | 0.1–0.2 mg/L | 2 mg/L |
| Chromium | 0–1 ug/L | 100 ug/L |
| Chlorate | 130–4306 ug/L | 800 ug/L |
| Bromide | 81–420 ug/L | — |
| Aluminum | 0–70 ug/L | — |
| Boron | 0.08–0.54 mg/L | 1 mg/L |
| Chromium, Hexavalent | 0–0.4 ug/L | — |
| Lithium | 0–13.6 ug/L | — |
| Manganese | 0–10 ug/L | — |
| Sodium | 3–6 mg/L | — |
| Vanadium | 14–19 ug/L | 50 ug/L |
| Cryptosporidium | 0–3 | — |
| Escherichia coli (E. coli) | 0 | — |
| Total Coliform | 3 | — |
| Perfluorobutanesulfonic acid | 0–11 ng/L | — |
| Perfluoroheptanoic acid | 0–4.6 ng/L | — |
| Perfluorohexanoic acid | 0–7.7 ng/L | — |
| Perfluoropentanoic acid | 0–7.3 ng/L | — |
| PFAS | 0–2.6 | — |
| PFBA | 0–15 ng/L | — |
| TOC | 2.9–12 mg/L | — |
| Gross Beta Particle Activity | 4.7–7.4 pCi/L | — |
| Uranium | 0–8.5 pCi/L | 20 pCi/L |
What this report doesn't tell you
10 of the 27 contaminants a community water system normally reports do not appear anywhere in Boulder, CO's data. Absent is not the same as absent-from-the-water — it means nobody published a number.
+Full detail: PFAS testing, water source, historical monitoring, and the federal violation record
Where your water comes from · EPA SDWIS
Boulder, CO buys its drinking water from BOULDER CITY OF.
Source
Treatment
Distribution
Also buys water from BOULDER CITY OF.
Compliance history
Federal Safe Drinking Water Act violation & enforcement records (EPA SDWIS). A violation is a regulatory determination by the state or EPA — separate from the measured levels above.
- Treatment technique violationHealth-based1 violation on record · most recent Nov 2018resolved
Source: EPA SDWIS / ECHO. View the full federal record on EPA ECHO ↗