Tap Water Quality Report
Tap water quality in OAK PARK, Illinois
Tap water in OAK PARK, Illinois receives a grade of C (75/100) from TapWaterSafety.org. It's served by OAK PARK. 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. Data sources: EPA SDWIS, EPA ECHO, EWG Tap Water Database.
What's in OAK PARK's tap water
Top water quality concerns identified by the EPA and Environmental Working Group across the utility serving 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.
EPA compliance record
Official U.S. EPA records for OAK PARK (system ID IL0312250) for the last 3 years. Checked 2026-10-07.
Source: U.S. EPA Enforcement and Compliance History Online (ECHO), from the Safe Drinking Water Information System. See EPA's full report.
Recommended filters for OAK PARK
Filters matched to the specific contaminants in OAK PARK's water supply.
Carbon filter certified for VOCs (NSF/ANSI 53)
$180-$599Activated carbon is effective for disinfection byproducts. Look for NSF/ANSI 53 VOC reduction.
Disclosure: TapWaterSafety earns a commission from purchases made through these links. This does not influence our scoring methodology or filter selection.
All contaminants detected in OAK PARK's tap water
Every contaminant identified, compared side-by-side against US EPA legal limits, the EU Drinking Water Directive (2020/2184), WHO Guidelines, and California's Public Health Goal. 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, California OEHHA PHGs, EWG Tap Water Database.
Treatment plant contact info
For service issues, water quality concerns, or to request a Consumer Confidence Report from OAK PARK.