C56/100
Mattoon Tap Water Quality: Is It Safe to Drink? (2026 Report)
Serving 28,400 residents · Illinois
What's In Mattoon's Tap Water?
69
Contaminants Tested
0
Exceed EPA Limits
0
Above EPA Goals
EPA Violation History
1
Violation (last 5yr)
0
Unresolved
0
Health-Related
TIER 3Resolved
Exceeded the MCL for disinfection byproducts
This is a paperwork/process violation — it does not mean a contaminant was detected at unsafe levels.
When: April 1, 2023 – June 30, 2023Enforcement: 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
CLEAR WATER SERVICE CORP
Population Served
8,900
Water Source
Groundwater
System ID
IL0295100
MATTOON
Population Served
19,500
Water Source
Surface Water
System ID
IL0290250
Frequently Asked Questions About Mattoon Water
Is Mattoon tap water safe to drink?
Mattoon, Illinois tap water receives a grade of C (56/100), which is considered fair. 0 contaminant(s) exceed EPA maximum contaminant levels and 33 violation(s) are on record. Residents should consider using an NSF-certified water filter to reduce contaminant exposure.
What contaminants are in Mattoon's water?
Of the 69 contaminants tested in Mattoon's water supply, the most notable include Lead (90th percentile). 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 Mattoon have any water quality violations?
Yes, Mattoon has 33 EPA violation(s) on record, with the most recent in 2025. Violation types include Other, MR, TT. 13 of these are health-based violations, which are the most serious category.
Do I need a water filter in Mattoon?
Mattoon 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 Mattoon's tap water come from?
Mattoon's drinking water is sourced from groundwater and supplied by CLEAR WATER SERVICE CORP and 1 other water system(s). The system serves approximately 28,400 people. Groundwater is pumped from underground aquifers, which often provides natural filtration.
How often is Mattoon'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. Mattoon'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 Mattoon's water compare to other cities in Illinois?
Mattoon's water quality score of 56/100 earns a grade of C, which is considered fair. This is a below-average score that indicates room for improvement. Visit our Illinois state page to see how all cities in the state compare.
What should I do if I'm concerned about Mattoon's water quality?
If you have concerns about Mattoon'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 (CLEAR WATER SERVICE CORP) 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.