Thornton, Colorado: Is the Tap Water Safe to Drink?
2026 EPA water quality data for 7 community water systems serving 230,829+ residents. See violations, PFAS results, lead test results, and safety grades — free.
Is Thornton Tap Water Safe to Drink?
Thornton has 7 community water systems. 6 of 7 graded systems meet all EPA standards (grade A or B), while 1 has recorded violations. No active health-based violations are currently open. Check individual system reports below for specifics.
Thornton Water Quality Overview
Thornton, Colorado is served by 7 community water systems providing water to approximately 230,829 residents. These systems draw from surface water purchased (3), groundwater (3), surface water (1) sources. Thornton water systems have recorded 5 health-based violations in their history, though none are currently active. Including monitoring and reporting violations, there are 284 total violations on record.
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All 7 water systems in Thornton
Looking for water quality data across the whole state? See our full Colorado tap water safety report covering Colorado’s EPA-regulated water systems.
Thornton Drinking Water: Frequently Asked Questions
Is Thornton, Colorado tap water safe to drink?
Thornton has 7 community water systems. 6 of 7 graded systems meet all EPA standards (grade A or B), while 1 has recorded violations. No active health-based violations are currently open. Check individual system reports below for specifics.
How many water utilities serve Thornton, Colorado?
7 community water systems serve Thornton, Colorado, providing water to approximately 230,829 people. Different neighborhoods may be served by different utilities. Enter your ZIP code at the top to find your specific provider.
Does Thornton tap water have lead?
Lead in drinking water typically enters from old pipes and fixtures inside homes and buildings, not from the treatment plant. The EPA requires water systems to monitor for lead under the Lead and Copper Rule. Click any water system above to see its most recent 90th-percentile lead test results. Homes built before 1986 are most likely to have lead plumbing components.
What contaminants have been found in Thornton drinking water?
EPA violation records for Thornton water systems are listed on each utility's report page. Common regulated contaminants include disinfection byproducts (TTHMs, HAA5), coliform bacteria, nitrates, and lead. Click any utility above to see its full violation history going back 10 years.
How do I find out which water company serves my address in Thornton?
Enter your Thornton ZIP code in the search box at the top of this page. ClearWater will identify the specific water system serving your area and show you its EPA violation history, lead test results, and an overall safety grade. You can also check your water bill or your utility's annual Consumer Confidence Report (CCR).