A93/100
St Charles Tap Water Quality: Is It Safe to Drink? (2026 Report)
Serving 73,040 residents · Missouri
What's In St Charles's Tap Water?
69
Contaminants Tested
0
Exceed EPA Limits
1
Above EPA Goals
1 contaminant above EPA health goals
| Contaminant | Detected | Limit (MCL) | Status |
|---|---|---|---|
chlorate | 348.00 µg/L | — | Above Goal |
EPA Violation History
1
Violation (last 5yr)
0
Unresolved
0
Health-Related
TIER 3Resolved
Monitoring / Reporting Violation
This is a paperwork/process violation — it does not mean a contaminant was detected at unsafe levels.
When: October 1, 2024 – April 2, 2025Rule: Ground Water RuleEnforcement: Resolving — corrective action underway
Understanding violation severity
Tier 1Urgent health risk. Utility must notify all customers within 24 hours.Tier 2Important health or treatment issue. Customers notified within 30 days.Tier 3Administrative or monitoring issue. Reported in the annual water quality report.
Source: EPA Safe Drinking Water Information System (SDWIS) · Updated quarterly
Water Utility Details
ST CHARLES PWS
Population Served
73,040
Water Source
Purchased Surface Water
System ID
MO6010707
Frequently Asked Questions About St Charles Water
Is St Charles tap water safe to drink?
St Charles, Missouri tap water receives a grade of A (93/100), which is considered excellent. Out of 69 contaminants tested, none exceed EPA maximum contaminant levels (MCLs) and 1 exceed health guidelines (MCLGs). While the water meets federal standards, some residents may still choose to use a filter for additional peace of mind.
What contaminants are in St Charles's water?
Of the 69 contaminants tested in St Charles's water supply, the most notable include chlorate. No contaminants exceed EPA legal limits. 1 contaminant(s) exceed EPA health goals (MCLGs), which are non-enforceable targets set at levels with no known health risk.
Does St Charles have any water quality violations?
Yes, St Charles has 4 EPA violation(s) on record, with the most recent in 2024. Violation types include MR, Other. None of these are classified as health-based violations.
Do I need a water filter in St Charles?
St Charles water meets EPA standards, so a filter is not strictly necessary. However, some residents prefer the added security of a water filter. EPA health goals (MCLGs) are stricter than legal limits and are set at levels with zero expected health risk. 1 contaminant(s) exceed these stricter goals.
Where does St Charles's tap water come from?
St Charles's drinking water is sourced from purchased surface water and supplied by ST CHARLES PWS. The system serves approximately 73,040 people. Surface water sources include rivers, lakes, and reservoirs.
How often is St Charles's water tested?
Under the Safe Drinking Water Act (SDWA), water utilities are required to regularly test for over 90 contaminants. Testing frequency varies by contaminant — some are tested monthly, others quarterly or annually. St Charles's water systems must report results to the EPA and publish an annual Consumer Confidence Report (CCR). The data on this page reflects the latest available EPA testing data.
How does St Charles's water compare to other cities in Missouri?
St Charles's water quality score of 93/100 earns a grade of A, which is considered excellent. This places St Charles among the better-performing water systems in Missouri. Visit our Missouri state page to see how all cities in the state compare.
What should I do if I'm concerned about St Charles's water quality?
If you have concerns about St Charles's tap water, consider these steps: (1) Request your utility's annual Consumer Confidence Report for detailed local data. (2) Get your water independently tested through a state-certified laboratory. (3) Consider an NSF-certified water filter rated for the contaminants found in your area. (4) Contact your water utility (ST CHARLES PWS) with specific questions. (5) Report water quality issues to your state drinking water program or the EPA Safe Drinking Water Hotline at 800-426-4791.