Is Oak Brook Terr, IL Tap Water Safe to Drink?
Graded B+ — but Copper was detected above EPA limits. Here's what's in the water and how to remove it. What to do next ↓
80.1/100
waterverge.com Oak Brook Terr, IL — Water Quality Report
Oak Brook Terr's drinking water received a grade of B+ (80.1 out of 100), indicating good water quality. The city's 2 water systems serve approximately 2,863 residents using purchased surface water.
Lead levels were measured at 0.0 ppb (90th percentile), well within EPA limits. This system has not yet been tested for PFAS under the EPA UCMR 5 program.
The system has 63 violations on record, including 7 health-based violations. 14 remain unresolved.
What to know about Oak Brook Terr's water
Oak Brook Terr ranks #566 out of 891 cities in Illinois for water quality, placing it below average in the state.
The city draws from surface water sources, which are more susceptible to seasonal runoff and agricultural contamination, requiring extensive multi-barrier treatment including coagulation, filtration, and disinfection.
As a small community water system, Oak Brook Terr may have fewer resources for advanced treatment technologies and infrastructure upgrades compared to larger utilities.
Water quality score
See methodology →Is Oak Brook Terr, IL water safe to drink?
Oak Brook Terr's drinking water has significant quality concerns based on EPA testing data. With a grade of B+ (80.1/100), the system has issues across multiple categories. A water filter is recommended for all residents. The city's 2 water systems serve approximately 2,863 residents using surface water (rivers, lakes, or reservoirs).
Recent water quality updates for Oak Brook Terr
A timeline of significant water quality events, violations, and data updates.
Latest EPA compliance and testing data incorporated into Oak Brook Terr's water quality assessment. Grade: B+ (80.1/100).
Contaminants: Consumer Confidence Rule.
Contaminants: Lead and Copper Rule.
Contaminants: Consumer Confidence Rule.
Federal disaster declaration (FEMA DR-4116). Flood event — may have impacted local water infrastructure.
Federal disaster declaration (FEMA DR-3230). Hurricane event — may have impacted local water infrastructure.
Key contaminant findings
Based on the most recent EPA sampling data for Oak Brook Terr's water supply.
Well within EPA limits.
Exceeds EPA action level. Copper can leach from household plumbing — flush taps for 30 seconds before drinking.
Violation history
Oak Brook Terr's water system has 63 total violations on record, including 7 health-based violations. 14 remain unresolved. 1 violation was issued in the last 5 years.
Flood & environmental risk
DuPage County has experienced 5 federally declared disasters since 1972. Flooding and severe storms can overwhelm water treatment plants, cause sewage overflows, and introduce agricultural runoff, bacteria, and sediment into drinking water supplies. Local water sources include Des Plaines River, Salt Creek, Addison Creek, Flag Creek, Sawmill Creek.
Where does Oak Brook Terr's water come from?
Oak Brook Terr's drinking water comes from surface water (rivers, lakes, or reservoirs), supplied by 2 water systems serving approximately 2,863 people. Surface water sources are more susceptible to contamination from runoff, industrial discharge, and algal blooms, requiring extensive treatment. Nearby water bodies include Des Plaines River (river), Salt Creek (river), Addison Creek (river), Flag Creek (river), Sawmill Creek (river).
What Oak Brook Terr residents can do
Recommended: NSF-certified water filter. This addresses the specific contaminants found in Oak Brook Terr's water.
Your water utility is required to publish an annual Consumer Confidence Report (CCR) with detailed testing results. Ask for the latest copy or check your utility's website.
Oak Brook Terr's area has a history of flooding. After severe weather, watch for boil water advisories from your local utility.
Data: EPA SDWIS, UCMR 5 (PFAS), FEMA, NOAA. Last updated May 2026.
Top contaminants to know
View all ↓Violation summary
Violations & advisories
Flood & disaster history
DuPage County has experienced 5 federally declared disasters since 1972. Flooding and severe weather can compromise water treatment infrastructure and introduce contaminants into drinking water supplies.
Recommended water filters
Based on contaminants detected in Oak Brook Terr's water supply, we recommend the following filter types.
Full contaminants report
| Contaminant | Detected Level | EPA Limit | Unit | Category | Status |
|---|---|---|---|---|---|
| Lead (90th percentile) LeadHeavy Metal A toxic heavy metal that can leach into drinking water from older pipes, solder, and fixtures. No amount of lead in water is considered safe. Health EffectsBrain and nervous system damage in children, kidney damage, high blood pressure, and reproductive problems in adults. EPA Limit15 ppb action level Common SourcesCorrosion of lead pipes, lead solder, brass faucets, and household plumbing. | 0.0 | 15 | ppb | Inorganic | Safe |
| Copper (90th percentile) CopperInorganic A metal that enters drinking water mainly through corrosion of copper plumbing. Small amounts are essential for health, but excess levels are harmful. Health EffectsGastrointestinal distress (nausea, vomiting, diarrhea) at short-term high levels; liver and kidney damage from long-term exposure. EPA Limit1.3 mg/L action level Common SourcesCorrosion of copper household plumbing, erosion of natural deposits. | 1.57 | 1.3 | mg/L | Inorganic | Over Limit |
Lead level trend (90th percentile)
Copper level (90th percentile)
Latest reading: 1.570 mg/L (2000)
EPA action level: 1.3 mg/L
See how Oak Brook Terr compares by contaminant
Explore where Oak Brook Terr ranks among all Illinois cities for specific contaminants.
Water source & infrastructure
Where Oak Brook Terr's water comes from
Oak Brook Terr's drinking water comes primarily from surface water sources such as rivers, lakes, or reservoirs.
Surface water systems require multi-stage treatment including coagulation, sedimentation, filtration, and disinfection to meet EPA Safe Drinking Water Act standards.
These sources can be impacted by seasonal changes, stormwater runoff, upstream agriculture, and industrial discharge.
The system is operated by local government ownership and serves approximately 2,863 people through 2 water systems.
Water bodies near Oak Brook Terr
Oak Brook Terr is located near 5 notable water bodies. As a surface water system, these water bodies may directly influence the city's drinking water supply.
Water systems serving Oak Brook Terr
| System Name | PWSID | Population | Source |
|---|---|---|---|
| OAKBROOK TERRACE | IL0430750 | 1,440 | SWP |
| YORK TOWNSHIP WATER SYSTEM | IL0430010 | 1,423 | SWP |
How Oak Brook Terr compares
Full Illinois rankings →Oak Brook Terr's score of 80.1/100 is above the average of 56/100 among major Illinois cities. It outscores 7 of 10 nearby cities.
Nearby cities
View Illinois rankings →About Oak Brook Terr, IL
Learn more about your water
Guides and resources related to Oak Brook Terr's water quality findings.
Explore water quality across Dupage
Frequently asked questions
Is Oak Brook Terr, IL tap water safe to drink?
Oak Brook Terr's water quality earned a grade of B+ (80.1/100). The water generally meets EPA standards and is considered safe for consumption. The city ranks #566 out of 891 cities tested in Illinois.
What contaminants are in Oak Brook Terr's water?
Lead was measured at 0.0 ppb (90th percentile). 63 violations are on record.
How is Oak Brook Terr's water quality grade calculated?
The grade is based on four factors: violation history (40%), lead and copper levels (25%), PFAS contamination (25%), and regulatory compliance (10%). The score is also adjusted based on how complete the available data is. See our methodology page for full details.
Do I need a water filter in Oak Brook Terr?
Based on current data, basic filtration should suffice for additional peace of mind.
Where does Oak Brook Terr's water come from?
Oak Brook Terr's water is sourced from Purchased surface water. The city has 2 water systems serving approximately 2,863 residents.
What health violations has Oak Brook Terr's water system had?
Oak Brook Terr has 7 health-based violations on record. The most recent violation was recorded in July 2025. Health-based violations mean the water exceeded EPA maximum contaminant levels (MCLs) for a regulated substance. 14 violations remain unresolved.
How does Oak Brook Terr's water compare to other cities?
Oak Brook Terr ranks #566 out of 891 cities in Illinois (better than 36% of state cities) and #8008 out of 15744 cities nationally (49th percentile). The grade of B+ reflects the combined assessment of violation history, lead and copper levels, PFAS contamination, and regulatory compliance.