Marion County, AL radon potential

EPA places Marion County in Zone 2 - Moderate Potential — a predicted county-wide average indoor radon level between 2 and 4 pCi/L, based on the geology, soil and aerial radioactivity data behind EPA's national map. Rank it against the rest of the country and Marion County lands in the 50th percentile for radon potential.

Where Marion County sits nationally

Marion County, Alabama is home to about 29,323 people across 742.342 square miles. That works out to roughly 40 people per square mile. Within its own EPA zone, Marion County is bigger by population than 53% of the counties that share it. Geologically, Marion 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 Marion County

Neither at the 4 pCi/L action level nor down at the roughly 1.3 pCi/L national indoor norm, Marion County's Zone 2 prediction lands in the gap between the two. Nothing about a Zone 2 label lowers the case for testing in Marion County — EPA recommends it in every zone, moderate included.

If Marion 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 Alabama's state radon program

For Marion County, an ongoing number beats a one-time test - a Airthings radon monitor tracks Marion 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 Marion 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.