Is Logan County, IL a radon risk area?

EPA's own radon map rates Logan County zone 1 - highest potential, predicting a county-wide average indoor level above 4 pCi/L. Nationally, Logan County ranks higher in radon potential than 84% of rated counties (the 84th percentile).

Logan County by the numbers

About 27,518 people live in Logan County, Illinois, spread over 618.052 square miles. Averaged across its land area, Logan County runs about 45 people per square mile. Rank 490 by population within its EPA zone puts Logan County at the 54th percentile among zone peers. Geologically, Logan County is grouped into EPA Region 5 alongside 523 other counties that share its rock and soil setting.

What this actually means for a house in Logan County

Fixing a home becomes an EPA recommendation past 4 pCi/L, and that is precisely the side of the line Logan County's Zone 1 prediction lands on, well above the roughly 1.3 pCi/L most US homes average. A Zone 1 rating means testing is worth doing sooner rather than later, but it is still county-wide average, not a reading for any single house — some homes in Logan County will test well under the action level, and EPA's guidance is to test regardless of zone.

Testing and mitigation in Logan County

Nothing about Logan County's EPA zone changes the mitigation number: $800–$2,500 nationally (around $1,200 typical), set by the house's foundation rather than the county it sits in — and only relevant once a test actually clears 4 pCi/L.

Find Illinois's state radon program

Logan County's test kit answers today; a Airthings radon monitor keeps answering for Logan County over time. Affiliate link, RadonZoneCheck earns a commission there, at no extra cost to you. Code RADONZONE-10OFF takes 10% off at checkout.

More on how this number was built

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