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

Wayne County is mapped as Zone 2 - Moderate Potential by EPA — meaning the county-wide average indoor level is predicted between 2 and 4 pCi/L. Nationally that's the 44th percentile for radon potential — Wayne County outranks 44% of every county EPA has rated.

Wayne County by the numbers

Wayne County, Illinois is home to about 15,928 people across 713.833 square miles. Population density there runs about 22 people per square mile. By population, Wayne County is the 696th largest of every county sharing its EPA zone — the 33rd percentile by population within that zone. Wayne County falls in EPA Radon Region 5, one of 524 counties nationally EPA assigns to that same geologic province.

Zone vs. an actual test

Call it a middle case: above the 1.3 pCi/L most US homes average, below the 4 pCi/L line EPA uses to recommend mitigation — that's Wayne County's Zone 2 prediction. Wayne County's Zone 2 rating sits in the middle nationally; EPA's guidance is unchanged by that — test every home regardless of its zone.

If Wayne County tests above the action level

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

Where Wayne 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 Wayne County carries, the zone explainer covers what it does and doesn't tell you about any one house.