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Tap water quality report

Oak Brook, IL

EPA monitoring detected 14 contaminants across the 2 water suppliers serving Oak Brook. A detection doesn't automatically mean the water is unsafe — see the level at the main supplier for each below, with its EPA source and period.

2
water suppliers
14,761
people served
14
contaminants found
Illinois rankings Lead in Illinois PFAS in Illinois

What was found in Oak Brook's water

The level at the city's main supplier, the highest level anywhere in the city, the EPA limit for each, and where every figure comes from.

ContaminantLevel vs EPA limitSuppliersSource
Copper
425.09999999999997 µg/L 33%
of the EPA limit 1300 µg/L
Main supplier: OAK BROOK · 9,400 people · 2017
1/2 SYR4
TTHM
55.309999999999995 µg/L 69%
of the EPA limit 80 µg/L
Main supplier: OAK BROOK · 9,400 people · 2019
1/2 SYR4
Chloroform
32.39999999999999 µg/L
No EPA limit set
Main supplier: OAK BROOK · 9,400 people · 2019
1/2 SYR4
Total Haloacetic Acids (HAA5)
23.17999999999999 µg/L 39%
of the EPA limit 60 µg/L
Main supplier: OAK BROOK · 9,400 people · 2019
1/2 SYR4
Bromodichloromethane
15.2 µg/L
No EPA limit set
Main supplier: OAK BROOK · 9,400 people · 2019
1/2 SYR4
Trichloroacetic Acid
11.079999999999998 µg/L
No EPA limit set
Main supplier: OAK BROOK · 9,400 people · 2019
1/2 SYR4
Dichloroacetic Acid
10.799999999999994 µg/L
No EPA limit set
Main supplier: OAK BROOK · 9,400 people · 2019
1/2 SYR4
Dibromochloromethane
8.982999999999999 µg/L
No EPA limit set
Main supplier: OAK BROOK · 9,400 people · 2019
1/2 SYR4
Lead
6.103999999999999 µg/L 41%
of the EPA limit 15 µg/L
Main supplier: OAK BROOK · 9,400 people · 2017
1/2 SYR4
Monochloroacetic Acid
3.8979999999999997 µg/L
No EPA limit set
Main supplier: OAK BROOK · 9,400 people · 2019
1/2 SYR4
Dibromoacetic Acid
1.81 µg/L
No EPA limit set
Main supplier: OAK BROOK · 9,400 people · 2019
1/2 SYR4
Monobromoacetic Acid
1.6899999999999993 µg/L
No EPA limit set
Main supplier: OAK BROOK · 9,400 people · 2019
1/2 SYR4
Bromoform
1.394 µg/L
No EPA limit set
Main supplier: OAK BROOK · 9,400 people · 2019
1/2 SYR4
Lead
0.00083 mg/L 5.5%
of the EPA limit 0.0150 mg/L
Main supplier: OAK BROOK · 9,400 people · 2025
Highest in the city: 0.0013 mg/L — AQUA ILLINOIS-OAK BROOK · 5,361 people · 2025
2/2 LCR
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 95th percentile of the system's samples — over 100% is worth reading, but is not by itself a violation. Formal violations are listed separately. These are the utilities' own EPA-reported results, not a city-wide average. A detection means the lab measured the substance — it isn't the same as exceeding a legal limit. Hover a source tag to see the EPA program and years behind each figure.

Water suppliers serving Oak Brook

SupplierPopulation served
OAK BROOK 9,400
AQUA ILLINOIS-OAK BROOK 5,361

Frequently asked questions about Oak Brook tap water

Is Oak Brook tap water safe to drink?

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

How many water suppliers serve Oak Brook?

2 public water suppliers report drinking-water monitoring for Oak Brook, Illinois to the EPA. Each is listed above with its population served.

What contaminants are in Oak Brook's water?

The contaminants EPA monitoring detected in Oak Brook include Copper, TTHM, Chloroform, Total Haloacetic Acids (HAA5), Bromodichloromethane. The full list, with the level at the main supplier and the data source, is in the table above.

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.