Gallatin County, IL radon potential

EPA's own radon map rates Gallatin County zone 2 - moderate potential, predicting a county-wide average indoor level between 2 and 4 pCi/L. Nationally that's the 36th percentile for radon potential — Gallatin County outranks 36% of every county EPA has rated.

Where Gallatin County sits nationally

Gallatin County, Illinois is home to about 4,690 people across 322.942 square miles. That works out to roughly 15 people per square mile. Within its own EPA zone, Gallatin County is bigger by population than 8% of the counties that share it. EPA's geology-based Region 5 groups Gallatin County with 523 other counties nationally sharing its underlying rock and soil profile.

What this actually means for a house in Gallatin County

Gallatin 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). Middle-of-the-pack doesn't mean risk-free for any one Gallatin County address — a moderate county average still leaves individual homes to test either side of it.

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

Where Gallatin County's figures come from

The methodology guide shows exactly which EPA and Census sources feed Gallatin County's numbers. If you're unsure why a low zone still deserves a test, the zone explainer covers that directly.