WaterQ
Illinois State Report All States
Official Status: March 2026

Is St. Charles tap water safe to drink?

⚠ Caution Advised
C

Use extra caution — St. Charles scores 55/100.

Safety Score
55
out of 100

Still not sure if you need a filter in St. Charles?

Read Decision Guide →

St. Charles

Illinois

View Illinois state report Data updated: Mar 2026

Is St. Charles tap water safe to drink?

Use extra caution — St. Charles scores 55/100. This report aggregates EPA drinking water data across 3 local systems in St. Charles. We found 115 total violations (72 unresolved).

🛡️ Home Water Treatment Needs

Should you invest in filtration or softening for your home in St. Charles?

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 St. Charles tap water needs filtering? We break it down.

Baby Formula Safety

Mixing baby formula with St. Charles tap water? Read this first.

Homebuyer's Perspective

If you're house-hunting in St. Charles, water quality belongs on your due-diligence checklist alongside schools and crime data. With a score of 55/100, we recommend budgeting for high-quality point-of-entry filtration systems to protect your home's value.

Property Impact: Requires Mitigation

Health & Family Safety

Residents should monitor Copper (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 St. Charles

115
Violations (5yr)
72
Unresolved
2
Contaminants Tracked
1
Exceeding EPA Limit

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

Frequently Asked Questions

Is St. Charles tap water safe to drink?

Use extra caution — St. Charles scores 55/100.

How many water systems serve St. Charles?

St. Charles is served by 3 public water systems in our latest EPA-backed dataset.

How can I check water quality for my exact address in St. Charles?

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

What is the water quality score for St. Charles?

The water quality score for St. Charles is 55 out of 100, based on EPA contaminant data, violation history, and testing results across the 3 systems serving the city.

What are the top contaminants in St. Charles?

The top contaminants detected in St. Charles include Copper (90th percentile), Lead (90th percentile). View detailed information on our contaminants page.

Water Quality Score
55/100
Grade
D
Water Systems
3
Population
38,987

St. Charles Water Quality Summary

St. Charles, IL receives a water quality score of 55/100 (Grade D) based on EPA Safe Drinking Water Information System (SDWIS) compliance data for 3 public water systems serving the area.

St. Charles's water quality score is below the national average, indicating a history of EPA violations or elevated contaminant levels. Residents are encouraged to check their specific water system report and consider additional filtration.

St. Charles's score of 55 is 11 points below the Illinois state average of 66, and below the nationwide average of roughly 78/100 across all U.S. states.

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

Key Contaminants

Copper (90th percentile) Violation
1.4 / 1.3 mg/L
0 mg/L MCL: 1.3 mg/L
Lead (90th percentile)
0.0033 / 0.015 mg/L
0 mg/L MCL: 0.015 mg/L

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Water Systems Serving St. Charles (3)

Related

Compare St. Charles water quality: View all states · Contaminant library · How we score water quality