Dupage County, Illinois: drinking water report. DuPage County sits immediately west of Chicago, home to about 930,000 residents in suburbs like Naperville,…
DuPage County sits immediately west of Chicago, home to about 930,000 residents in suburbs like Naperville, Wheaton, and Downers Grove. The DuPage Water Commission purchases and distributes Lake Michigan water to most of the county, though some western communities maintain independent groundwater wells.
Lake Michigan water delivered through the DuPage Water Commission is well-treated and consistent. The commission operates a pumping station in Elmhurst that receives water from Chicago's system and distributes it across the county. UCMR5 data shows low-level PFAS detections in some county systems – primarily those with supplemental groundwater sources.
According to the Illinois EPA's 2024 compliance data, DuPage County water systems met all federal contaminant limits. The county does not host major military installations, and PFAS sources are primarily diffuse. Argonne National Laboratory in the southwest part of the county has a documented contamination history, though primarily involving radionuclides rather than PFAS.
DuPage County residents on the Lake Michigan system benefit from one of the strongest source water supplies in the Midwest.
Check your water to confirm your source and see monitoring data. For most residents, a carbon filter for taste improvement is sufficient. Our water filter guide covers options for different needs. Pull your detailed report, and visit our Illinois page for statewide data.
Drinking water is one exposure route. These federal datasets also cover Dupage County, IL.
The EPA places Dupage County, IL in Zone 2 - a moderate-risk category, with a predicted average indoor radon level between 2 and 4 pCi/L. Zone maps predict an area's radon potential from geology and existing indoor readings; they say nothing about a specific house. Testing is the only way to know your own level.
55% of homes in Dupage County, IL were built before 1980, and 8% before 1950. Residential lead paint was banned in 1978, so housing age is the strongest available proxy for lead-paint exposure. This describes the county's housing stock, not any one home.
Modelled annual fine-particle pollution (PM2.5) in Dupage County, IL averages 9.1 µg/m³, above the EPA's annual standard of 9 µg/m³. These are CDC modelled county estimates rather than readings from a specific monitor.
How radon zones work · Air quality by county · Lead exposure guide