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

Crawford 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. That puts Crawford County in the 45th percentile nationally for radon potential — higher than 45% of the counties EPA has rated.

Crawford County by the numbers

Crawford County, Illinois is home to about 18,388 people across 443.643 square miles. Population density there runs about 41 people per square mile. By population, Crawford County is the 654th largest of every county sharing its EPA zone — the 37th percentile by population within that zone. Crawford County falls in EPA Radon Region 5, one of 524 counties nationally EPA assigns to that same geologic province.

Zone vs. an actual test

Crawford County's predicted average falls between EPA's 4 pCi/L action level and the national indoor average of about 1.3 pCi/L (outdoor air runs roughly 0.4 pCi/L). A Zone 2 rating is a moderate county-wide average, not a guarantee about any one house in Crawford County — testing is the only way to know an individual home's actual level.

If Crawford County tests above the action level

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

Where Crawford 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. The guide to what a radon zone actually means covers why testing matters in every zone, not just Zone 1.