B73/100
Oak Brook Tap Water Quality: Is It Safe to Drink? (2026 Report)
Serving 12,070 residents · Illinois
What's In Oak Brook'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 |
|---|---|---|---|
Lead (90th percentile) | < 0.001 mg/L | 0.015 mg/L | Above Goal |
EPA Violation History
3
Violations (last 5yr)
0
Unresolved
0
Health-Related
TIER 3Resolved
Surface water treatment technique failure
When: July 1, 2024 – June 11, 2025Enforcement: 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
TIER 3Resolved
Failed to issue ongoing public notification
This is a paperwork/process violation — it does not mean a contaminant was detected at unsafe levels.
When: October 1, 2023 – February 27, 2024Rule: 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
SUBURBAN APARTMENTS (DE KALB UNIV DVL)
Population Served
1,050
Water Source
Groundwater
System ID
IL0375148
OAK BROOK
Population Served
9,400
Water Source
Purchased Surface Water
System ID
IL0430700
NORTHFIELD ESTATES
Population Served
1,620
Water Source
Groundwater
System ID
MI0040594
Frequently Asked Questions About Oak Brook Water
Is Oak Brook tap water safe to drink?
Oak Brook, Illinois tap water receives a grade of B (73/100), which is considered good. Out of 70 contaminants tested, 1 exceed EPA maximum contaminant levels (MCLs) and 2 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 Oak Brook's water?
Of the 70 contaminants tested in Oak Brook'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 Oak Brook have any water quality violations?
Yes, Oak Brook has 43 EPA violation(s) on record, with the most recent in 2025. Violation types include Other, MR, MON. 6 of these are health-based violations, which are the most serious category.
Do I need a water filter in Oak Brook?
Based on EPA data, using a water filter in Oak Brook 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 Oak Brook's tap water come from?
Oak Brook's drinking water is sourced from groundwater and supplied by SUBURBAN APARTMENTS (DE KALB UNIV DVL) and 2 other water system(s). The system serves approximately 12,070 people. Groundwater is pumped from underground aquifers, which often provides natural filtration.
How often is Oak Brook'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. Oak Brook'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 Oak Brook's water compare to other cities in Illinois?
Oak Brook's water quality score of 73/100 earns a grade of B, which is considered good. This is an above-average score compared to many cities nationwide. Visit our Illinois state page to see how all cities in the state compare.
What should I do if I'm concerned about Oak Brook's water quality?
If you have concerns about Oak Brook'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 (SUBURBAN APARTMENTS (DE KALB UNIV DVL)) 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.