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

Shannon 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. Nationally, Shannon County ranks higher in radon potential than 37% of rated counties (the 37th percentile).

Shannon County by the numbers

Shannon County, Missouri is home to about 7,275 people across 1,003.82 square miles. Averaged across its land area, Shannon County runs about 7 people per square mile. By population, Shannon County is the 894th largest of every county sharing its EPA zone — the 13th percentile by population within that zone. Shannon 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 Shannon County

Neither at the 4 pCi/L action level nor down at the roughly 1.3 pCi/L national indoor norm, Shannon County's Zone 2 prediction lands in the gap between the two. Middle-of-the-pack doesn't mean risk-free for any one Shannon County address — a moderate county average still leaves individual homes to test either side of it.

Testing and mitigation in Shannon County

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

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