Will County, IL: EPA's radon zone, explained

EPA's own radon map rates Will County zone 2 - moderate potential, predicting a county-wide average indoor level between 2 and 4 pCi/L. Nationally, Will County ranks higher in radon potential than 65% of rated counties (the 65th percentile).

Will County by the numbers

Will County, Illinois is home to about 708,583 people across 835.908 square miles. Population density there runs about 848 people per square mile. By population, Will County is the 34th largest of every county sharing its EPA zone — the 97th percentile by population within that zone. EPA's geology-based Region 5 groups Will County with 523 other counties nationally sharing its underlying rock and soil profile.

Why the zone isn't the answer by itself

EPA's Zone 2 rating for Will County sits below its own 4 pCi/L action level but above the national indoor average of about 1.3 pCi/L. Nothing about a Zone 2 label lowers the case for testing in Will County — EPA recommends it in every zone, moderate included.

Next steps for a home in Will County

For a Will County homeowner, the order is simple: test first, since a kit costs a small fraction of what mitigation would. Only if the result clears 4 pCi/L does a system — typically $800–$2,500, about $1,200 for a common install — become worth pricing out.

Find Illinois's state radon program

For Will County, an ongoing number beats a one-time test - a Airthings radon monitor tracks Will County's levels over time. RadonZoneCheck earns a commission there, at no extra cost to you. RADONZONE-10OFF at checkout knocks 10% off.

Where Will County's figures come from

Every figure on this page traces to EPA's own Map of Radon Zones and Census data, documented in the methodology guide. Whatever zone Will County carries, the zone explainer covers what it does and doesn't tell you about any one house.