Drinking water quality · 2024
· Verified
· PWSID CO0101833
What's in Thornton, CO tap water
Only 9 of 27 core regulated contaminants were reported for Thornton, CO. What was measured is clean — but most of the picture is missing.
- !2 contaminants within 20% of a limit
- !9 of 27 core regulated contaminants reported — 18 never appear in this report
- ✓Nothing over a federal limit
- ✓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.
- −0 contaminants at or above a federal limit
- −8 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
- −16 core regulated contaminants never reported (9/27)
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
- Chlorine98% of the federal limit1.7–3.9 mg/L · limit 4 mg/L
Effective and necessary, but high residual levels can cause taste and odor issues; the EPA caps the residual disinfectant level.
higher than 95% of U.S. systems
- PFOA98% of the federal limit0–3.9 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 35% of U.S. systems
+15 contaminants were measured and came in below the limitShow all
| Contaminant | Measured | Federal limit |
|---|---|---|
| TTHM | 17.4–50.7 ug/L | 80 ug/L |
| PFOS | 0–2.5 ng/L | 4 ng/L |
| Bromate | 0–2.3 ug/L | 10 ug/L |
| HAA5 | 4.8–12.9 ug/L | 60 ug/L |
| Fluoride | 0.5–0.8 mg/L | 4 mg/L |
| Nitrate | 0.1–0.8 mg/L | 10 mg/L |
| Nitrite | 0–0.05 mg/L | 1 mg/L |
| Hexafluoropropylene oxide dimer acid | 0.1–0.3 ng/L | 10 ng/L |
| Perfluorohexanesulfonic acid | 0.1–0.3 ng/L | 10 ng/L |
| Perfluorononanoic acid | 0.1–0.3 ng/L | 10 ng/L |
| Barium | 43–52 ug/L | 2000 ug/L |
| Selenium | 0.8–1.3 ug/L | 50 ug/L |
| Total Coliform | 99.9 % | — |
| Perfluorobutanesulfonic acid | 0.1–0.3 | — |
| TOC | 0.8–2.2 | — |
What this report doesn't tell you
18 of the 27 contaminants a community water system normally reports do not appear anywhere in Thornton, 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
Thornton, CO buys its drinking water from THORNTON CITY OF.
Source
Treatment
Distribution
Also buys water from THORNTON 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.