WaterQ
Colorado State Report All States
Official Status: March 2026

Is Thornton tap water safe to drink?

✓ Generally Safe
B

Mostly yes — Thornton scores 84/100.

Safety Score
84
out of 100

Still not sure if you need a filter in Thornton?

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Thornton

Colorado

View Colorado state report Data updated: Mar 2026

Is Thornton tap water safe to drink?

Mostly yes — Thornton scores 84/100. This report aggregates EPA drinking water data across 4 local systems in Thornton. We found 110 total violations (8 unresolved).

Real-Time Environment

Live: 03:15 PM
0mm Precipitation

☀️ No active precipitation. Rainfall can impact surface water turbidity and pollutant runoff in Thornton.

Water Quality Impact

✅ Minimal Impact Localized weather conditions may influence test result variability.

🛡️ Home Water Treatment Needs

Should you invest in filtration or softening for your home in Thornton?

Requirement Status
Recommended
🟡
💡

Expert Advice

Given the safety margin, a Carbon Block or sediment filter is recommended to improve taste and remove trace particulates.

Buying a Filter?

Wondering if Thornton tap water needs filtering? We break it down.

Baby Formula Safety

Mixing baby formula with Thornton tap water? Read this first.

Homebuyer's Perspective

If you're house-hunting in Thornton, water quality belongs on your due-diligence checklist alongside schools and crime data. The high safety score (84/100) suggests lower risk for plumbing corrosion and appliance scaling.

Property Impact: Positive / Stable

Health & Family Safety

Residents should monitor Lead (90th percentile) levels. Pregnant women and families with young children should consult the specific EPA health goals listed below.

View Health Risk Glossary →

Compliance Record for Thornton

110
Violations (5yr)
8
Unresolved
1
Contaminants Tracked
0
Exceeding EPA Limit

Based on EPA SDWIS violation records and contaminant test results for all water systems serving Thornton.

Frequently Asked Questions

Is Thornton tap water safe to drink?

Mostly yes — Thornton scores 84/100.

How many water systems serve Thornton?

Thornton is served by 4 public water systems in our latest EPA-backed dataset.

How can I check water quality for my exact address in Thornton?

Use the WaterQ search tool to look up your ZIP code and view nearby systems, contaminant levels, and recent violations for Thornton.

What is the water quality score for Thornton?

The water quality score for Thornton is 84 out of 100, based on EPA contaminant data, violation history, and testing results across the 4 systems serving the city.

What are the top contaminants in Thornton?

The top contaminants detected in Thornton include Lead (90th percentile). View detailed information on our contaminants page.

Water Quality Score
84/100
Grade
B
Water Systems
4
Population
230,551

Thornton Water Quality Summary

Thornton, CO receives a water quality score of 84/100 (Grade B) based on EPA Safe Drinking Water Information System (SDWIS) compliance data for 4 public water systems serving the area.

Thornton's water quality is above the national average, with strong compliance records and low contaminant levels. Residents generally receive clean, safe tap water that meets EPA standards.

Thornton's score of 84 is 2 points above the Colorado state average of 82, and above the nationwide average of roughly 78/100 across all U.S. states.

For homebuyers looking at Thornton, Colorado, the municipal water profile reflects both the benefits and challenges of its Mountain West setting. While residents of this mid-size city benefit from water drawn from high-elevation sources, the region's historic hardrock mining legacy requires ongoing monitoring across the multiple systems serving the area. Overall, the tap water achieves a solid, above-average rating that indicates generally reliable quality, though prospective property owners should still verify which specific local system services their prospective home.

Water quality data is sourced from the U.S. EPA SDWIS database and updated quarterly. Learn about our scoring methodology → Read our Colorado water quality rankings report →

Key Contaminants

Lead (90th percentile)
0.003 / 0.015 mg/L
0 mg/L MCL: 0.015 mg/L

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Water Systems Serving Thornton (4)

Related

Compare Thornton water quality: View all states · Contaminant library · How we score water quality