Dallas County, MO radon potential

Dallas 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 that's the 45th percentile for radon potential — Dallas County outranks 45% of every county EPA has rated.

How Dallas County compares

Dallas County, Missouri is home to about 17,877 people across 540.951 square miles. Averaged across its land area, Dallas County runs about 33 people per square mile. Within its own EPA zone, Dallas County is bigger by population than 36% of the counties that share it. EPA's geology-based Region 7 groups Dallas County with 411 other counties nationally sharing its underlying rock and soil profile.

Zone vs. an actual test

EPA's Zone 2 rating for Dallas County sits below its own 4 pCi/L action level but above the national indoor average of about 1.3 pCi/L. Dallas County's Zone 2 rating sits in the middle nationally; EPA's guidance is unchanged by that — test every home regardless of its zone.

Next steps for a home in Dallas 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 Dallas County, an ongoing number beats a one-time test - a Airthings radon monitor tracks Dallas County's levels over time. RadonZoneCheck earns a commission there, at no extra cost to you. Use code RADONZONE-10OFF at checkout for 10% off.

Where Dallas County's figures come from

Dallas County's zone, rank and region all trace back to named EPA and Census sources — the methodology guide lists exactly which ones. The guide to what a radon zone actually means covers why testing matters in every zone, not just Zone 1.