Thornton, Colorado Water Quality Report
Water quality data for 6 water systems serving 230,602 people.
Water Source
Detected Contaminants
| Contaminant | Detected Level | EPA Limit (MCL) | Health Guideline | % of Limit | Status |
|---|---|---|---|---|---|
| lithium | 34.0 | No federal limit | 10.0 ug/L(EPA/USGS HBSL) | 340% | Above guideline |
| PFBA | 0.010 | No federal limit | 1000.0 ug/L(EWG) | 0% | Below guideline |
| PFBS | 0.008 | No federal limit | 2000.0 ug/L(EPA Health Advisory) | 0% | Below guideline |
| PFHpA | 0.004 | No federal limit | 1000.0 ug/L(EWG) | 0% | Below guideline |
| PFHxA | 0.013 | No federal limit | 1000.0 ug/L(EWG) | 0% | Below guideline |
| PFHxS | 0.006 | 0.010 ug/L | 0.001 ug/L(EWG) | 59% | Within limit |
| PFOA | 0.007 | 0.004 ug/L | 0.090 ug/L(EWG) | 178% | Above limit |
| PFOS | 0.005 | 0.004 ug/L | 0.300 ug/L(EWG) | 125% | Above limit |
| PFPeA | 0.012 | No federal limit | 1000.0 ug/L(EWG) | 0% | Below guideline |
Recommended Water Filters
Based on the contaminants detected in your water supply, these filtration systems are recommended:
Reverse Osmosis (RO)
Reverse osmosis systems remove up to 99% of PFAS compounds. Recommended for homes with detected PFAS.
Up to 99% PFAS removal
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Compliance & Violations
Active Violations (6)
71
Jul 1, 2025
71
Jul 1, 2025
51
Jan 1, 2025
51
Jan 1, 2025
5A
Oct 11, 2024
5A
Oct 11, 2024
Resolved Violations (494)
76
Jul 17, 2025
76
Jul 17, 2025
03
Jul 1, 2025 — Sep 30, 2025
03
Jul 1, 2025 — Sep 30, 2025
03
Jul 1, 2025 — Sep 30, 2025
+ 489 more resolved violations
Frequently Asked Questions
Is Thornton tap water safe to drink?
Thornton's water has 2 contaminants detected above EPA limits. While the water is treated, residents may want to consider additional filtration.
What contaminants are in Thornton tap water?
9 contaminants have been detected in Thornton's water supply across 6 water systems. See the full contaminant table above for details.
How can I improve my water quality in Thornton?
Install a water filter rated for the specific contaminants found in Thornton's water. See our filter recommendations above. You can also request your utility's Consumer Confidence Report for the most current test results.
Does Thornton have any water quality violations?
Yes, Thornton currently has 10 active violations. See the violations section above for details.