A85/100
Lisle Tap Water Quality: Is It Safe to Drink? (2026 Report)
Serving 24,233 residents · Illinois
What's In Lisle's Tap Water?
69
Contaminants Tested
0
Exceed EPA Limits
0
Above EPA Goals
EPA Violation History
2
Violations (last 5yr)
1
Unresolved
0
Health-Related
TIER 3Unresolved
Surface water treatment technique failure
TIER 3Resolved
Surface water treatment technique failure
When: July 1, 2021 – October 28, 2021Enforcement: 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
LISLE
Population Served
24,233
Water Source
Purchased Surface Water
System ID
IL0430551
Frequently Asked Questions About Lisle Water
Is Lisle tap water safe to drink?
Lisle, Illinois tap water receives a grade of A (85/100), which is considered excellent. Out of 69 contaminants tested, none exceed EPA maximum contaminant levels (MCLs). While the water meets federal standards, some residents may still choose to use a filter for additional peace of mind.
What contaminants are in Lisle's water?
69 contaminants were tested in Lisle's water supply. No contaminants exceed EPA legal limits (MCLs) or health goals (MCLGs), which is a positive indicator of water quality.
Does Lisle have any water quality violations?
Yes, Lisle has 7 EPA violation(s) on record, with the most recent in 2025. Violation types include Other, MCL, MR. 2 of these are health-based violations, which are the most serious category.
Do I need a water filter in Lisle?
Lisle 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. All contaminants are within health goals.
Where does Lisle's tap water come from?
Lisle's drinking water is sourced from purchased surface water and supplied by LISLE. The system serves approximately 24,233 people. Surface water sources include rivers, lakes, and reservoirs.
How often is Lisle'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. Lisle'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 Lisle's water compare to other cities in Illinois?
Lisle's water quality score of 85/100 earns a grade of A, which is considered excellent. This places Lisle among the better-performing water systems in Illinois. Visit our Illinois state page to see how all cities in the state compare.
What should I do if I'm concerned about Lisle's water quality?
If you have concerns about Lisle'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 (LISLE) 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.