F0/100
Wonder Lake Tap Water Quality: Is It Safe to Drink? (2026 Report)
Serving 5,820 residents · Illinois
What's In Wonder Lake's Tap Water?
32
Contaminants Tested
1
Exceed EPA Limits
1
Above EPA Goals
2 contaminants above EPA health goals
| Contaminant | Detected | Limit (MCL) | Status |
|---|---|---|---|
Copper (90th percentile) | 1.90 mg/L | 1.30 mg/L | Over Limit |
Lead (90th percentile) | 0.003 mg/L | 0.015 mg/L | Above Goal |
EPA Violation History
5
Violations (last 5yr)
1
Unresolved
1
Health-Related
TIER 3Unresolved
Failed to issue ongoing public notification
This is a paperwork/process violation — it does not mean a contaminant was detected at unsafe levels.
When: July 1, 2025Rule: Ground Water RuleEnforcement: Informal — resolved cooperativelyVerify on EPA.gov
TIER 3Resolved
Monitoring / Reporting Violation
This is a paperwork/process violation — it does not mean a contaminant was detected at unsafe levels.
When: April 1, 2025 – August 27, 2025Rule: Ground Water RuleEnforcement: Resolving — corrective action underway
TIER 3Resolved
Disinfection byproduct treatment technique failure
When: February 10, 2024 – April 8, 2024Rule: Ground Water RuleEnforcement: Resolving — corrective action underway
TIER 2Resolved
Consumer confidence report — content deficiency
When: April 2, 2023 – June 22, 2023Rule: Ground Water RuleEnforcement: Resolving — corrective action underway
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: January 1, 2022 – December 31, 2022Enforcement: 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
WONDER LAKE
Population Served
3,870
Water Source
Groundwater
System ID
IL1115750
WONDER LAKE (NIU)
Population Served
1,950
Water Source
Groundwater
System ID
IL1115850
Frequently Asked Questions About Wonder Lake Water
Is Wonder Lake tap water safe to drink?
Wonder Lake, Illinois tap water receives a grade of F (0/100), which is considered failing. 1 contaminant(s) exceed EPA maximum contaminant levels and 169 violation(s) are on record. Residents should consider using an NSF-certified water filter to reduce contaminant exposure.
What contaminants are in Wonder Lake's water?
Of the 32 contaminants tested in Wonder Lake's water supply, the most notable include Copper (90th percentile), Lead (90th percentile). 1 contaminant(s) exceed EPA legal limits (MCLs). 2 contaminant(s) exceed EPA health goals (MCLGs), which are non-enforceable targets set at levels with no known health risk.
Does Wonder Lake have any water quality violations?
Yes, Wonder Lake has 169 EPA violation(s) on record, with the most recent in 2025. Violation types include MR, MON, Other. 6 of these are health-based violations, which are the most serious category.
Do I need a water filter in Wonder Lake?
Based on EPA data, using a water filter in Wonder Lake is recommended. 1 contaminant(s) exceed legal limits. An NSF-certified filter — such as a reverse osmosis or activated carbon system — can effectively reduce many common contaminants. Choose a filter certified to remove the specific contaminants found in your area.
Where does Wonder Lake's tap water come from?
Wonder Lake's drinking water is sourced from groundwater and supplied by WONDER LAKE and 1 other water system(s). The system serves approximately 5,820 people. Groundwater is pumped from underground aquifers, which often provides natural filtration.
How often is Wonder Lake'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. Wonder Lake'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 Wonder Lake's water compare to other cities in Illinois?
Wonder Lake's water quality score of 0/100 earns a grade of F, which is considered failing. This is a concerning score that suggests significant water quality issues. Visit our Illinois state page to see how all cities in the state compare.
What should I do if I'm concerned about Wonder Lake's water quality?
If you have concerns about Wonder Lake'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 (WONDER LAKE) 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.