Marshall County, AL radon potential

Marshall 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. Marshall County sits at the 60th percentile nationally for radon potential — above 60 of every 100 rated counties.

Marshall County by the numbers

Marshall County, Alabama is home to about 102,156 people across 565.854 square miles. That works out to roughly 181 people per square mile. Within its own EPA zone, Marshall County is bigger by population than 81% of the counties that share it. Geologically, Marshall County is grouped into EPA Region 4 alongside 735 other counties that share its rock and soil setting.

What this actually means for a house in Marshall County

EPA's Zone 2 rating for Marshall County sits below its own 4 pCi/L action level but above the national indoor average of about 1.3 pCi/L. Marshall County's Zone 2 rating sits in the middle nationally; EPA's guidance is unchanged by that — test every home regardless of its zone.

Testing and mitigation in Marshall 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 Alabama's state radon program

For Marshall County, an ongoing number beats a one-time test - a Airthings radon monitor tracks Marshall 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 Marshall County's figures come from

The methodology guide shows exactly which EPA and Census sources feed Marshall County's numbers. Whatever zone Marshall County carries, the zone explainer covers what it does and doesn't tell you about any one house.