- EPA's UCMR 5 testing looked for 30 contaminants here and found 9.
- Lithium: found in 7 of 7 samples, average 27 µg/L, highest 34 µg/L (EPA UCMR 5 testing, Feb 2023–Nov 2023)
- PFPeA (a PFAS): found in 7 of 7 samples, average 8.1 ppt, highest 12.4 ppt (EPA UCMR 5 testing, Feb 2023–Nov 2023)
- PFBA (a PFAS): found in 6 of 7 samples, average 7.3 ppt, highest 10.4 ppt (EPA UCMR 5 testing, Feb 2023–Nov 2023)
- PFHxA (a PFAS): found in 7 of 7 samples, average 7.3 ppt, highest 12.6 ppt (EPA UCMR 5 testing, Feb 2023–Nov 2023)
- PFBS (a PFAS): found in 7 of 7 samples, average 4.9 ppt, highest 8.1 ppt (EPA UCMR 5 testing, Feb 2023–Nov 2023)
- PFOA (a PFAS): found in 2 of 7 samples, average 1.9 ppt, highest 7.1 ppt (EPA UCMR 5 testing, Feb 2023–Nov 2023)
- PFHxS (a PFAS): found in 2 of 7 samples, average 1.4 ppt, highest 5.9 ppt (EPA UCMR 5 testing, Feb 2023–Nov 2023)
- PFOS (a PFAS): found in 2 of 7 samples, average 1.4 ppt, highest 5 ppt (EPA UCMR 5 testing, Feb 2023–Nov 2023)
- PFHpA (a PFAS): found in 2 of 7 samples, average 1 ppt, highest 3.7 ppt (EPA UCMR 5 testing, Feb 2023–Nov 2023)
- Lead, 90th percentile: 2.3 ppb at the latest result in EPA records for a monitoring period that ran on or after July 1, 2021, at or below EPA's 15 ppb action level (EPA SDWIS, monitoring period Jan 1, 2025–Dec 31, 2025). The 90th percentile is a system-wide measure from homes sampled under EPA's lead rule; it isn't a result for your home.
Public EPA test results
Can you drink Thornton tap water? What EPA records show
EPA CO0101150 · serves Adams County, CO · about 226,465 people (EPA SDWIS)
This report shows EPA's federal records for this water system: UCMR 5 testing, lead testing and violations. It isn't a test of the water at your tap, and it has no Water Score.
Public EPA test results
Thornton City of (EPA CO0101150)
ScoreYourWater.com gives no verdict on your tap water; it shows what the public records say, as of October 14, 2026. For Thornton's main utility, Thornton City of: We found no health-based violations in EPA's records for this system (CO0101150) since July 1, 2021, as of October 14, 2026. EPA's UCMR 5 testing looked for 30 contaminants here and found 9.
What EPA records show for Thornton City of, as of October 14, 2026
We found no health-based violations in EPA's records for this system (CO0101150) since July 1, 2021, as of October 14, 2026.
Source: EPA ECHO record for Thornton City of (SDWIS). Data as of October 14, 2026.
Lead, 90th percentile: 2.3 ppb at the latest result in EPA records for a monitoring period that ran on or after July 1, 2021, at or below EPA's 15 ppb action level (EPA SDWIS, monitoring period Jan 1, 2025–Dec 31, 2025). The 90th percentile is a system-wide measure from homes sampled under EPA's lead rule; it isn't a result for your home.
EPA's UCMR 5 testing looked for 30 contaminants here and found 9.
Source: EPA records (SDWIS, UCMR 5). SDWIS: data as of Oct 14, 2026. EPA UCMR 5 data, samples through June 2026.
Your water bill names your utility.
Does Thornton City of use chloramine?
EPA treatment records (state-reported) list chloramines for Thornton City of. EPA record