Macoupin County, IL radon potential

EPA's own radon map rates Macoupin County zone 2 - moderate potential, predicting a county-wide average indoor level between 2 and 4 pCi/L. Nationally that's the 54th percentile for radon potential — Macoupin County outranks 54% of every county EPA has rated.

Macoupin County by the numbers

Macoupin County, Illinois is home to about 43,895 people across 862.995 square miles. Averaged across its land area, Macoupin County runs about 51 people per square mile. Within its own EPA zone, Macoupin County is bigger by population than 64% of the counties that share it. Geologically, Macoupin County is grouped into EPA Region 5 alongside 523 other counties that share its rock and soil setting.

Why the zone isn't the answer by itself

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 Macoupin County's Zone 2 prediction. A county-wide moderate average, like Macoupin County's, can still hide a specific house well above or below it — testing is what actually answers the question.

Next steps for a home in Macoupin County

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 Macoupin County, an ongoing number beats a one-time test - a Airthings radon monitor tracks Macoupin 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 Macoupin 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. If you're unsure why a low zone still deserves a test, the zone explainer covers that directly.