DeKalb County, MO: EPA's radon zone, explained

EPA's own radon map rates DeKalb County zone 2 - moderate potential, predicting a county-wide average indoor level between 2 and 4 pCi/L. Nationally, DeKalb County ranks higher in radon potential than 40% of rated counties (the 40th percentile).

How DeKalb County compares

DeKalb County, Missouri is home to about 9,884 people across 421.358 square miles. Population density there runs about 23 people per square mile. By population, DeKalb County is the 817th largest of every county sharing its EPA zone — the 21st percentile by population within that zone. DeKalb County falls in EPA Radon Region 7, one of 412 counties nationally EPA assigns to that same geologic province.

Zone vs. an actual test

EPA's Zone 2 rating for DeKalb County sits below its own 4 pCi/L action level but above the national indoor average of about 1.3 pCi/L. Nothing about a Zone 2 label lowers the case for testing in DeKalb County — EPA recommends it in every zone, moderate included.

Testing and mitigation in DeKalb County

For a DeKalb County homeowner, the order is simple: test first, since a kit costs a small fraction of what mitigation would. Only if the result clears 4 pCi/L does a system — typically $800–$2,500, about $1,200 for a common install — become worth pricing out.

Find Missouri's state radon program

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

Where DeKalb County's figures come from

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