Madison County, TN radon potential

Madison County is mapped as Zone 3 - Low Potential by EPA — meaning the county-wide average indoor level is predicted below 2 pCi/L. Nationally, Madison County ranks higher in radon potential than 26% of rated counties (the 26th percentile).

How Madison County compares

Madison County, Tennessee is home to about 100,409 people across 557.174 square miles. That works out to roughly 180 people per square mile. Within its own EPA zone, Madison County is bigger by population than 79% of the counties that share it. Geologically, Madison County is grouped into EPA Region 4 alongside 735 other counties that share its rock and soil setting.

Why the zone isn't the answer by itself

A Zone 3 county like Madison County is predicted closer to the 0.4 pCi/L typical outdoors than to EPA's 4 pCi/L action level. Low doesn't mean zero: EPA's own data shows homes in Zone 3 counties like Madison County testing above the action level often enough that skipping a test isn't the safe assumption.

Next steps for a home in Madison 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 Tennessee's state radon program

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

Where Madison County's figures come from

Madison County's zone, rank and region all trace back to named EPA and Census sources — the methodology guide lists exactly which ones. Whatever zone Madison County carries, the zone explainer covers what it does and doesn't tell you about any one house.