Edwards County, IL radon potential
EPA places Edwards County in Zone 2 - Moderate Potential — a predicted county-wide average indoor radon level between 2 and 4 pCi/L, based on the geology, soil and aerial radioactivity data behind EPA's national map. That puts Edwards County in the 37th percentile nationally for radon potential — higher than 37% of the counties EPA has rated.
Where Edwards County sits nationally
Edwards County, Illinois is home to about 5,984 people across 222.4 square miles. Averaged across its land area, Edwards County runs about 27 people per square mile. Within its own EPA zone, Edwards County is bigger by population than 11% of the counties that share it. EPA's geology-based Region 5 groups Edwards County with 523 other counties nationally sharing its underlying rock and soil profile.
What this actually means for a house in Edwards County
Edwards County's Zone 2 prediction clears the 1.3 pCi/L national indoor average without reaching EPA's own 4 pCi/L point for recommending a fix. A county-wide moderate average, like Edwards County's, can still hide a specific house well above or below it — testing is what actually answers the question.
If Edwards County tests above the action level
A short-term test kit is the standard first step and typically costs far less than mitigation itself. If a test comes back at or above 4 pCi/L, a radon mitigation system for a typical home runs roughly $800–$2,500 (around $1,200 for a common single-family install), driven mainly by foundation type, not by county.
Find Illinois's state radon program
For Edwards County, an ongoing number beats a one-time test - a Airthings radon monitor tracks Edwards County's levels over time. RadonZoneCheck earns a commission there, at no extra cost to you. RADONZONE-10OFF at checkout knocks 10% off.
Where Edwards County's figures come from
The methodology guide shows exactly which EPA and Census sources feed Edwards County's numbers. If you're unsure why a low zone still deserves a test, the zone explainer covers that directly.