Drinking water quality · 2024
· Verified
What's in Thornton, CO tap water
18 contaminants were measured in the Thornton, CO water system's 2024 annual report. Each is shown below against its federal limit — 1 sit at or above that limit.
- Reporting year
- 2024
- Contaminants measured
- 18
- Over federal limit
- 1
- Approaching the limit
- 0
- Worst contaminant
- Copper
- Service area
- CO
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.
Metals
| Contaminant | Measured | Federal limit | Status |
|---|---|---|---|
| CopperA metal that enters water from corroding household plumbing. | 0–1300 ug/LRangeSystem-wide | 1300 ug/LAction level | At or above the limit |
| BariumA metal from erosion of natural deposits and industrial discharge. | 43–52 ug/LRangeSystem-wide | 2000 ug/LMCL | Within the limit |
| SeleniumA trace element from natural deposits and industrial discharge. | 0.8–1.3 ug/LRangeSystem-wide | None set | Within the limit |
PFAS ("forever chemicals")
| Contaminant | Measured | Federal limit | Status |
|---|---|---|---|
| PFOAPerfluorooctanoic acid, a PFAS 'forever chemical' once used in nonstick and stain-resistant products. | 0–3 ng/LRangeSystem-wide | 0 ng/LMCLG | Within the limit |
| PFOSPerfluorooctanesulfonic acid, a PFAS 'forever chemical' once used in firefighting foam and coatings. | 0–1.9 ng/LRangeSystem-wide | 0 ng/LMCLG | Within the limit |
| Hexafluoropropylene oxide dimer acidHFPO-DA ('GenX chemicals'), a newer-generation PFAS replacement compound. | 0.1–0.3RangeSystem-wide | None set | Detected — no federal limit |
| Perfluorobutanesulfonic acidPerfluorobutanesulfonic acid, a shorter-chain PFAS 'forever chemical.' | 0.1–0.3RangeSystem-wide | None set | Detected — no federal limit |
| Perfluorohexanesulfonic acidPerfluorohexanesulfonic acid, a PFAS 'forever chemical.' | 0.1–0.3RangeSystem-wide | None set | Detected — no federal limit |
| Perfluorononanoic acidPerfluorononanoic acid, a PFAS 'forever chemical.' | 0.1–0.3RangeSystem-wide | None set | Detected — no federal limit |
Disinfectants
| Contaminant | Measured | Federal limit | Status |
|---|---|---|---|
| ChlorineA disinfectant added to drinking water to kill bacteria and viruses. | 1.7–2.9 mg/LRangeSystem-wide | 4 mg/LMCLG | Within the limit |
Disinfection byproducts
| Contaminant | Measured | Federal limit | Status |
|---|---|---|---|
| TTHMTotal trihalomethanes — a group of four chemicals (including chloroform) formed when chlorine reacts with natural organic matter. | 17.4–36.3 ug/LRangeSystem-wide | None set | Within the limit |
| HAA5Haloacetic acids — a group of five disinfection byproducts formed when disinfectants react with organic matter. | 4.8–9 ug/LRangeSystem-wide | None set | Within the limit |
| BromateA disinfection byproduct formed when bromide-containing water is treated with ozone. | 0–0 ug/LRangeSystem-wide | 0 ug/LMCLG | None detected |
Inorganic chemicals
| Contaminant | Measured | Federal limit | Status |
|---|---|---|---|
| FluorideA mineral often added to drinking water to help prevent tooth decay. | 0.5–0.8 mg/LRangeSystem-wide | 4 mg/LMCL | Within the limit |
| NitrateA compound from fertilizer runoff, septic systems, and erosion of natural deposits. | 0.1–0.8 mg/LRangeSystem-wide | 10 mg/LMCL | Within the limit |
| NitriteA compound from fertilizer runoff, sewage, and erosion of natural deposits. | 0–0.05 mg/LRangeSystem-wide | 1 mg/LMCL | Within the limit |
Microbial
| Contaminant | Measured | Federal limit | Status |
|---|---|---|---|
| Total ColiformA group of bacteria used as an indicator of overall water-system sanitation. | 99.9 %RangeSystem-wide | None set | Detected — no federal limit |
Physical & aggregate
| Contaminant | Measured | Federal limit | Status |
|---|---|---|---|
| TOCTotal organic carbon — a measure of organic material dissolved in the water. | 0.8–1.8RangeSystem-wide | None set | Detected — no federal limit |
People also ask about Thornton, CO's water
+Is Thornton, CO tap water safe to drink in 2024?
The 2024 Consumer Confidence Report for the Thornton, CO water utility lists 1 contaminant at or above the federal limit: Copper. Whether that means the water is "unsafe" depends on which contaminant, how long the exposure, and individual health factors. The table on this page shows the measured value, the federal threshold, and the regulated statistic used for compliance.
+What contaminants are in Thornton, CO tap water?
18 contaminants were measured in Thornton, CO's 2024 Consumer Confidence Report, spanning pfas ("forever chemicals"), disinfection byproducts, and inorganic chemicals. 8 have an enforceable federal limit; the rest are detected but unregulated. Every measured value, in the utility's own units, is on this page.
+Which contaminants exceed federal limits in Thornton, CO tap water?
One contaminant in Thornton, CO's 2024 report sits at or above the federal limit: Copper (1.0× the limit). The EPA enforces these limits against the regulated reporting statistic — typically a running annual average or 90th percentile — not a one-off sample spike.
+What is the worst contaminant in Thornton, CO tap water?
The contaminant with the highest measured value relative to its federal limit in the 2024 report is Copper, at 1.0× the federal threshold. It belongs to the metals family of contaminants.
+Where does the data on this page come from?
Every value is transcribed from Thornton, CO's 2024 Consumer Confidence Report — the annual drinking-water report every U.S. public water utility is required by federal law to publish. The original source document is archived and viewable on this site. A water-quality report covers an entire service area, not a single address.
+How often is Thornton, CO's water quality data updated?
Each U.S. public water utility publishes one Consumer Confidence Report per year, covering the prior calendar year's measurements. This page reflects the 2024 report; a new report will replace it once the utility publishes its next annual update.