City water profile
Compare local ZIP estimates, evidence quality, associated public systems, and compliance history for Thornton, Colorado.
Median indexed hardness
47PPM
5 indexed ZIPs
Range 44.4–50.2 PPM
City summary
Thornton has 5 published ZIP profiles across Adams County. The indexed median is 47 PPM, compared with 59 PPM across Colorado.
Among the 58 Coloradocities with an indexed median, Thornton ranks #46from highest to lowest. Across all 161 state ZIP profiles, available estimates run from 13.7to 829 PPM.
The 44.4–50.2 PPM range shows how much the available ZIP estimates vary within the city label.
Hardness distribution
5 of 5 ZIP profiles have a hardness estimate. Bars count ZIP profiles, not households or laboratory samples.
Evidence quality
Confidence labels
Observation window: Jan 5, 2016 to Jun 2, 2026.
ZIP directory
Open a ZIP for site-level provenance and measurements.
ZIP code
50.2 PPM
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ZIP code
47.1 PPM
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ZIP code
45 PPM
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ZIP code
50.2 PPM
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ZIP code
44.4 PPM
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Public water systems
PWSID CO0101150
A municipal system, in-state city, and served county all agree with this Census ZCTA.
PWSID CO0101833
The system names this served city; Census place overlap links the city to this ZCTA.
PWSID CO0101667
The system names this served city; Census place overlap links the city to this ZCTA.
PWSID CO0101320
The system names this served city; Census place overlap links the city to this ZCTA.
PWSID CO0101126
The system names this served city; Census place overlap links the city to this ZCTA.
PWSID CO0101078
The system names this served city; Census place overlap links the city to this ZCTA.
PWSID CO0101741
The system names this served city; Census place overlap links the city to this ZCTA.
Compliance history
No active health-based violation appears among the associated systems in the represented EPA reporting quarter. This does not mean every contaminant was tested at every tap.
| Record | System | Period | Status |
|---|---|---|---|
| Lead and Copper Rule | CO0101741 | Jan 1, 2026 | Resolved |
| Lead and Copper Rule | CO0101078 | Oct 1, 2025 | Resolved |
| Chloramine | CO0101126 | Jan 1, 2024 | Resolved |
| Surface Water Treatment Rule | CO0101126 | Jan 1, 2024 | Resolved |
| Interim Enhanced Surface Water Treatment Rule | CO0101150 | Nov 1, 2023 | Resolved |
| Interim Enhanced Surface Water Treatment Rule | CO0101150 | Oct 1, 2023 | Resolved |
| Lead and Copper Rule | CO0101126 | Oct 1, 2023 | Resolved |
| Interim Enhanced Surface Water Treatment Rule | CO0101150 | Sep 1, 2023 | Resolved |
| Lead and Copper Rule | CO0101150 | Jul 1, 2023 | Resolved |
| Lead and Copper Rule | CO0101126 | Jul 1, 2023 | Resolved |
Practical next steps
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Questions people ask
The indexed city median is 47 PPM. Open the ZIP report to verify the distance and confidence behind that estimate.
Compliance history is utility-wide and cannot guarantee conditions at every tap. Check current notices and test when address-specific evidence is needed.
Choose treatment only after confirming the problem at the property. A softener targets hardness; contaminant treatment requires a matching, verified performance claim.