Water Quality Report · Updated May 12, 2026
OAK PARK
OAK PARK delivers tap water graded C (67/100) by TapWaterSafety.org. The utility serves approximately 54,583 residents in OAK PARK, Illinois using surface water (purchased). The most significant water quality concerns are: Haloacetic acids (HAA9) significantly above health guideline; Total trihalomethanes (TTHMs) significantly above health guideline; Bromodichloromethane significantly above health guideline. For questions, the utility can be reached at 708-358-5704.
Is OAK PARK tap water safe to drink?
OAK PARK delivers tap water that earns a grade of C (67/100) from TapWaterSafety.org — an average rating, with several contaminants above health guidelines but generally compliant with US legal limits.
The utility serves 54,583 residents in OAK PARK, drawing from surface water (purchased).
Public testing data identifies 13 contaminants in this water above EWG's health-based guidelines, including: Haloacetic acids (HAA9), Total trihalomethanes (TTHMs), Bromodichloromethane, Haloacetic acids (HAA5), Trichloroacetic acid, Dibromochloromethane, Chloroform, Dibromoacetic acid, Dichloroacetic acid, Radium, combined (-226 and -228)*, Chromium (hexavalent), Nitrate*, Nitrate and nitrite*. For most residents, a properly certified home filter at the kitchen tap is the most cost-effective way to reduce exposure to whatever's in your water. See our filter recommendations below, matched specifically to this utility's contaminant profile.
Quick actions for OAK PARK residents
Top concerns in this water
Based on the most recent EPA and EWG data, these are the most significant water quality issues for OAK PARK.
Haloacetic acids (HAA9) significantly above health guideline
Moderate concernHaloacetic acids (HAA9) detected at 22.0 ppb, 366x above the EWG health guideline of 0.06 ppb.
Total trihalomethanes (TTHMs) significantly above health guideline
Moderate concernTotal trihalomethanes (TTHMs) detected at 31.3 ppb, 209x above the EWG health guideline of 0.15 ppb.
Bromodichloromethane significantly above health guideline
Moderate concernBromodichloromethane detected at 9.79 ppb, 163x above the EWG health guideline of 0.06 ppb.
Contact OAK PARK
Reach the utility directly for service issues, water quality concerns, or to request your Consumer Confidence Report.
General Contact
Treatment Plant
Recommended water filters for OAK PARK
Filters matched to the specific contaminants in this water supply.
Carbon block (NSF/ANSI 42 + 53)
$40-$750Activated carbon is highly effective for disinfection byproducts like TTHM and HAA5.
Disclosure: TapWaterSafety earns a commission from purchases made through these links. This does not influence our scoring methodology or filter selection.
Score breakdown
This utility's overall score of 67/100 breaks down across five weighted components. Read the full methodology →
Contaminants detected — international standards comparison
Every contaminant detected, compared side-by-side against US EPA legal limits, the EU Drinking Water Directive (2020/2184), WHO Guidelines, and California's Public Health Goal (the strictest US benchmark). Why we show multiple standards →
| Contaminant | Detected | EWG US health-based |
EPA US legal |
EU DWD Europe |
WHO global |
CA PHG strictest US |
Tested sample year |
Status |
|---|---|---|---|---|---|---|---|---|
| Haloacetic acids (HAA9) Disinfection byproduct |
22.0 ppb | 0.06 | — | — | — | — | — | 366× over |
| Total trihalomethanes (TTHMs) Disinfection byproduct |
31.3 ppb | 0.15 | 80.0 | 100 | — | — | — | 209× over |
| Bromodichloromethane Disinfection byproduct |
9.79 ppb | 0.06 | — | — | — | — | — | 163× over |
| Haloacetic acids (HAA5) Disinfection byproduct |
15.0 ppb | 0.1 | 60.0 | 60 | — | — | — | 150× over |
| Trichloroacetic acid Disinfection byproduct |
6.35 ppb | 0.1 | — | — | — | — | — | 64× over |
| Dibromochloromethane Disinfection byproduct |
5.42 ppb | 0.1 | — | — | — | — | — | 54× over |
| Chloroform Disinfection byproduct |
16.1 ppb | 0.4 | — | — | — | — | — | 40× over |
| Dibromoacetic acid Disinfection byproduct |
1.16 ppb | 0.03 | — | — | — | — | — | 39× over |
| Dichloroacetic acid Disinfection byproduct |
7.15 ppb | 0.2 | — | — | — | — | — | 36× over |
| Radium, combined (-226 and -228)* Radiological |
0.89 pCi/L | 0.05 | 5.0 | — | — | — | — | 18× over |
| Chromium (hexavalent) Heavy metal |
0.191 ppb | 0.02 | — | — | — | — | — | 9.6× over |
| Nitrate* Inorganic |
0.297 ppm | 0.14 | 10.0 | 11.3 | 11.3 | 10 | — | 2.1× over |
| Nitrate and nitrite* Inorganic |
0.297 ppm | 0.14 | 10.0 | 11.3 | 11.3 | 10 | — | 2.1× over |
| Bromoform Disinfection byproduct |
0.0479 ppb | 0.5 | — | — | — | — | — | Below guideline |
| Barium* Heavy metal |
19.7 ppb | 700.0 | 2000.0 | — | 1300 | 2000 | — | Below guideline |
| Molybdenum Other |
0.863 ppb | 40.0 | — | — | — | — | — | Below guideline |
| Vanadium Other |
0.25 ppb | 21.0 | — | — | — | — | — | Below guideline |
| Monobromoacetic acid Disinfection byproduct |
0.135 ppb | 25.0 | — | — | — | — | — | Below guideline |
| Monochloroacetic acid Disinfection byproduct |
0.182 ppb | 53.0 | — | — | — | — | — | Below guideline |
| Manganese Heavy metal |
0.14 ppb | 100.0 | — | 50 | 80 | — | — | Below guideline |
| Strontium Radiological |
0.125 ppb | 1500.0 | — | — | — | — | — | Below guideline |
| 4-Androstene-3,17-dione* Other |
0.175 ppt | — | — | — | — | — | — | Below guideline |
| Fluoride* Inorganic |
0.66 ppm | — | 4.0 | 1.5 | 1.5 | — | — | Below guideline |
| Quinoline Other |
0.006 ppb | — | — | — | — | — | — | Below guideline |
| Testosterone* Other |
0.025 ppt | — | — | — | — | — | — | Below guideline |
All values in the unit of the detected level. Red cells indicate the detected level exceeds that standard. Some contaminants have limits in some jurisdictions but not others (shown as —). The "Tested" column shows the year each contaminant sample was collected.
Sources: US EPA, EU Drinking Water Directive 2020/2184, WHO Guidelines (4th ed.), California OEHHA PHGs, EWG Tap Water Database.
OAK PARK service area
This water system serves 1 community in Cook County, Illinois. Click any city for its dedicated tap water quality page.
Find the right filter for OAK PARK water
Browse filter categories by water-quality concern. Each option below is NSF-certified for the matched contaminant type.