Maries County, MO radon potential

Maries 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. That puts Maries County in the 39th percentile nationally for radon potential — higher than 39% of the counties EPA has rated.

Where Maries County sits nationally

Maries County, Missouri is home to about 8,506 people across 526.981 square miles. That works out to roughly 16 people per square mile. Within its own EPA zone, Maries County is bigger by population than 17% of the counties that share it. EPA's geology-based Region 7 groups Maries County with 411 other counties nationally sharing its underlying rock and soil profile.

What this actually means for a house in Maries County

Call it a middle case: above the 1.3 pCi/L most US homes average, below the 4 pCi/L line EPA uses to recommend mitigation — that's Maries County's Zone 2 prediction. A Zone 2 rating is a moderate county-wide average, not a guarantee about any one house in Maries County — testing is the only way to know an individual home's actual level.

Testing and mitigation in Maries 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 Maries County, an ongoing number beats a one-time test - a Airthings radon monitor tracks Maries 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 Maries County's figures come from

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