Is Oak Brook Tap Water Safe? Quality Report

Water source: SWP
Ownership: Local government
Counties served: DuPage

Compliance record

Formal violations the EPA has on file for this supplier. A health-based violation means a contaminant limit or a required treatment was breached; the rest are monitoring or reporting failures — still violations, but not a measured health risk.

health-based violations

violations on file

still open

Violation	Type	Status	Period
MCL	Health-based	Resolved	1989-10-01 → 1993-09-30
MCL	Health-based	Resolved	1989-10-01 → 1993-09-30
MCL	Health-based	Resolved	1989-10-01 → 1993-09-30
MCL	Health-based	Resolved	1989-10-01 → 1993-09-30
MCL	Health-based	Resolved	1989-10-01 → 1993-09-30
MCL	Health-based	Resolved	1989-10-01 → 1993-09-30
MCL	Health-based	Resolved	1989-10-01 → 1993-09-30
MCL	Health-based	Resolved	1989-10-01 → 1993-09-30
MCL	Health-based	Resolved	1989-10-01 → 1993-09-30
MCL	Health-based	Resolved	1989-10-01 → 1993-09-30

Other contaminants detected

Each bar shows the measured level as a share of the EPA limit: green is well under, amber is close to it, red is over. For lead and copper the limit applies to exactly the 90th-percentile figure shown, so red there means a real exceedance. For everything else the limit applies to a running annual average while the figure is the single worst sample on record — over 100% is worth reading, but is not by itself a violation. Formal violations are listed separately.

Contaminant	Level vs EPA limit	Detection rate	Source	Period
Bromodichloromethane	17.6 µg/L No EPA limit set	119/119	SYR4	2012–2019
Chloroform	39.2 µg/L No EPA limit set	119/119	SYR4	2012–2019
Dibromochloromethane	9.91 µg/L No EPA limit set	119/119	SYR4	2012–2019
TTHM	64.8 µg/L 81% of the EPA limit 80 µg/L	119/119	SYR4	2012–2019
Total Haloacetic Acids (HAA5)	29.6 µg/L 49% of the EPA limit 60 µg/L	118/119	SYR4	2012–2019
Dichloroacetic Acid	13.8 µg/L No EPA limit set	117/119	SYR4	2012–2019
Trichloroacetic Acid	12.7 µg/L No EPA limit set	109/119	SYR4	2012–2019
Monobromoacetic Acid	2.15 µg/L No EPA limit set	69/119	SYR4	2012–2019
Dibromoacetic Acid	2.04 µg/L No EPA limit set	41/119	SYR4	2012–2019
Lead	0.00083 mg/L 5.5% of the EPA limit 0.0150 mg/L	14/14	LCR	2025
Copper	444 µg/L 34% of the EPA limit 1300 µg/L	10/60	SYR4	2014–2017
Bromoform	1.41 µg/L No EPA limit set	9/119	SYR4	2012–2019
Monochloroacetic Acid	4.05 µg/L No EPA limit set	9/119	SYR4	2012–2019
Lead	6.56 µg/L 44% of the EPA limit 15 µg/L	4/60	SYR4	2014–2017

30 contaminants tested, none detected

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Utility contact

Contact: O'MALLEY, TIM
Phone: 630-368-5276
Email: tomalley@oak-brook.org

Frequently asked questions about Oak Brook

Is Oak Brook tap water safe to drink?

EPA monitoring detected 14 contaminants in Oak Brook's water. A detection isn't the same as a violation — most levels are within federal limits. See each level and source above, and the utility's annual Consumer Confidence Report for its official compliance status.

What contaminants were detected in Oak Brook's water?

EPA monitoring detected Bromodichloromethane, Chloroform, Dibromochloromethane, TTHM, Total Haloacetic Acids (HAA5), and others. The full list with the level and data source for each is above.

How many people does Oak Brook serve?

Oak Brook reports serving 9,400 people in Illinois, per its EPA record.

Has Oak Brook had any water quality violations?

The EPA has 50 violations on file for Oak Brook, of which 35 are health-based (a contaminant limit or required treatment was breached) and 0 remain open. The rest are monitoring or reporting failures.

Where does this data come from?

Every figure is official EPA drinking-water monitoring — the Lead & Copper Rule, the UCMR-5 nationwide testing program, and the EPA Six-Year Review — not our own testing. Each number is labelled with its source and period.