Will County, Illinois: drinking water report. Will County lies southwest of Chicago, home to about 700,000 residents in communities like Joliet, Naperville…
Will County lies southwest of Chicago, home to about 700,000 residents in communities like Joliet, Naperville (partially), and Bolingbrook. Water sources are split – some communities purchase Lake Michigan water through the DuPage Water Commission or the Illinois American Water system, while others draw from deep sandstone aquifers or the Des Plaines and Kankakee Rivers.
Will County's groundwater systems face a challenge that Lake Michigan communities do not: aquifer depletion. The deep sandstone aquifers serving southwestern suburbs have been declining for decades as pumping has outpaced recharge. Some communities have been forced to seek alternative surface water connections.
UCMR5 data shows PFAS detections in several county systems. The Joliet Army Training Area and the former Joliet Arsenal are documented contamination sources. According to the Illinois EPA's 2024 monitoring data, three public water systems in Will County reported PFAS above detection thresholds. The former arsenal site, now the Midewin National Tallgrass Prairie, is undergoing long-term remediation.
Knowing whether your provider draws from Lake Michigan or local aquifers is the critical first question. The answer determines both quality and long-term supply reliability.
Check your water for data specific to your provider. For PFAS near the former arsenal site, reverse osmosis provides strong household protection. Our water filter guide covers options. Pull your detailed report, and visit our Illinois page for statewide data.
Drinking water is one exposure route. These federal datasets also cover Will County, IL.
The EPA places Will 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.
38% of homes in Will County, IL were built before 1980, and 10% 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 Will County, IL averages 9 µg/m³, within 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