Shelby County, MO radon potential

EPA places Shelby 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. Shelby County sits at the 36th percentile nationally for radon potential — above 36 of every 100 rated counties.

Shelby County by the numbers

Shelby County, Missouri is home to about 5,926 people across 500.863 square miles. Averaged across its land area, Shelby County runs about 12 people per square mile. Within its own EPA zone, Shelby County is bigger by population than 11% of the counties that share it. Shelby County falls in EPA Radon Region 7, one of 412 counties nationally EPA assigns to that same geologic province.

What this actually means for a house in Shelby County

Shelby County's Zone 2 prediction clears the 1.3 pCi/L national indoor average without reaching EPA's own 4 pCi/L point for recommending a fix. Nothing about a Zone 2 label lowers the case for testing in Shelby County — EPA recommends it in every zone, moderate included.

Testing and mitigation in Shelby 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 Missouri's state radon program

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