B79/100
MOKENA — Water Quality Report 2026
Serving 19,887 people · Illinois
Water Source
Purchased Surface Water
County
—
System ID
IL1970600
Violations
13
Contaminant Test Results
EPA Violation History
3
Violations (last 5yr)
1
Unresolved
0
Health-Related
TIER 3Resolved
Failed Level 2 Assessment under Revised Total Coliform Rule
This is a paperwork/process violation — it does not mean a contaminant was detected at unsafe levels.
When: July 1, 2024 – September 30, 2024Rule: Stage 2 DBPREnforcement: Resolving — corrective action underway
TIER 3Resolved
Failed Level 2 Assessment under Revised Total Coliform Rule
This is a paperwork/process violation — it does not mean a contaminant was detected at unsafe levels.
When: July 1, 2024 – September 30, 2024Rule: Stage 2 DBPREnforcement: 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
Frequently Asked Questions About MOKENA
Is MOKENA water safe to drink?
MOKENA water receives a grade of B (79/100), which is considered good. Out of 69 contaminants tested, none exceed EPA legal limits. The water meets federal safety standards.
What contaminants has MOKENA detected?
69 contaminants were tested in MOKENA's water. No contaminants exceed EPA legal limits or health goals, indicating good water quality management.
Does MOKENA have any EPA violations?
Yes, MOKENA has 13 EPA violation(s) on record, with the most recent in 2025. Violation types include Other, MR, MON. 2 are health-based violations.
How many people does MOKENA serve?
MOKENA serves approximately 19,887 people, Illinois. The system provides water to 1 community: Mokena.
What type of water does MOKENA provide?
MOKENA sources its water from purchased surface water. Surface water comes from rivers, lakes, or reservoirs and typically requires more extensive treatment. The utility's system ID is IL1970600.
How does MOKENA compare to other utilities in Illinois?
MOKENA scores 79/100 with a grade of B (good). This is an above-average performance for utilities statewide. Visit our Illinois state page for a full comparison of water systems.