Adams County, CO · PWSID CO0101150
City of Thornton lead service lines
No lead lines reported
City of Thornton reported 43,826 service lines and no lead, galvanized-requiring-replacement or unknown lines. That's good news for the service line. Older homes can still have lead solder or brass fixtures inside, so testing is the only sure check.
0% of City of Thornton's service lines are lead or galvanized requiring replacement. That's lower than the Colorado average (1.2%) and lower than the national average (3.1%).
- Lead 0%
- Galvanized (replace) 0%
- Unknown 0%
- Non-lead 100%
Total service lines reported: 43,826. Reported all required service line types. Population served: 226,465; 42,530 connections.
Lead test results
City of Thornton's most recent 90th-percentile lead result (2025) was 2.3 ppb, below both the 15 ppb action level and the 10 ppb level that takes effect in 2027. This means 90% of homes sampled were at or below that level; individual homes, especially those with lead lines, can be higher.
Lead and Copper Rule 90th-percentile results reported to EPA, in parts per billion. Dashed lines: 15 ppb action level and the 10 ppb level from November 1, 2027.
Lead rule violations
EPA's data lists 1 Lead and Copper Rule violation since 2015 for City of Thornton. Health-based violations are treatment failures, such as corrosion control or public education; the rest are missed monitoring or reporting.
| Began | Violation | Status |
|---|---|---|
| Jul 2023 | Missed follow-up or routine lead and copper tap sampling | Returned to compliance |
Source: EPA SDWIS violation records for the Lead and Copper Rule.
Where the water comes from
City of Thornton's main water source is surface water (rivers, lakes or reservoirs). It sells water to 9 other water systems: City of Brighton, City of Westminster, Friendly Village of the Rockies, The Grove at Alta Ridge, Pine Lakes Ranch, Redwood Estates, Woodland Hills MHC, Avilla Eastlake, Thornton Estates.
Source: EPA SDWIS water system and facility records.
Check your own address
These counts cover the whole system. To see whether your line is lead, use the utility's address-level inventory. Utilities had to prepare one by October 16, 2024 and make it publicly accessible; systems serving more than 50,000 people must post it online.
No map yet? Do the 2-minute scratch and magnet test on the pipe where water enters your home.
Protect your drinking water now
If your line is lead, galvanized or unknown, filter water for drinking, cooking and baby formula. Use a filter certified to NSF/ANSI 53 for lead. Run cold water for a few minutes after it sits for hours, and never use hot tap water for cooking.
How to pick a lead-certified filter · How to test your water for lead
Getting the line replaced
EPA's Lead and Copper Rule Improvements require most systems to replace lead and galvanized-requiring-replacement lines by December 31, 2037. Ask City of Thornton whether it replaces the private side for free or with a cost share before you hire anyone. If you want it done sooner, or your utility doesn't cover your side, a licensed plumber can quote it. What replacement costs.
County pages: Lead pipes in Adams County
Cities served
ZIP codes served
ZIP codes whose center falls inside City of Thornton's mapped service area (EPA service area boundaries). Neighboring utilities may serve parts of the same ZIP.
80233802418026080602
Other water systems nearby
| System | Lead + galv. | Unknown |
|---|---|---|
| City of Westminster | 1 | 8 |
| South Adams County WSD | 0 | 0 |
| City of Brighton | 0 | 1,730 |
| Pioneer Mobile Home Park | 0 | 109 |
| High Plains Wua | 0 | 31 |
| Derby Village Mobile Home Park | 0 | 30 |
| Hope Ditch Co | 0 | 4 |
| Northside Village MHP | 0 | 27 |
Check another water system
Questions
Does City of Thornton have lead pipes?
City of Thornton reported no lead, galvanized-requiring-replacement or unknown service lines among 43,826 lines.
How do I check if my home's service line is lead?
Look up your address on City of Thornton's official service line inventory, which utilities must make publicly available. You can also scratch the pipe where it enters your home: lead is soft, dull gray, scratches to shiny silver and does not attract a magnet.
When will City of Thornton replace lead service lines?
Under EPA's Lead and Copper Rule Improvements, most systems must replace lead and galvanized-requiring-replacement lines by December 31, 2037, starting from November 1, 2027. The rule is being challenged in court, so dates could change. Many utilities run free or cost-share programs now.
Has City of Thornton had lead violations?
EPA's data shows 1 Lead and Copper Rule violation since 2015 for City of Thornton.
Which water filters remove lead?
Use a filter certified to NSF/ANSI Standard 53 for lead reduction, or NSF/ANSI 58 for reverse osmosis. Check the certification on NSF's listings, not just the box.
Embed or cite this data
Local news sites, blogs and community groups can embed this card. It updates when EPA releases new data.
Citation: Lead Pipe Map, "City of Thornton lead service lines," https://leadpipemap.com/co/city-of-thornton/. Source: EPA SDWIS service line inventory, 2026 Q3. Download the full dataset on the data page.