Smith County, KS radon potential

EPA places Smith County in Zone 1 - Highest Potential — a predicted county-wide average indoor radon level above 4 pCi/L, based on the geology, soil and aerial radioactivity data behind EPA's national map. Nationally, Smith County ranks higher in radon potential than 69% of rated counties (the 69th percentile).

Smith County by the numbers

Smith County, Kansas is home to about 3,541 people across 895.464 square miles. Averaged across its land area, Smith County runs about 4 people per square mile. Within its own EPA zone, Smith County is bigger by population than 9% of the counties that share it. Smith County falls in EPA Radon Region 7, one of 412 counties nationally EPA assigns to that same geologic province.

Why the zone isn't the answer by itself

Smith County carries a Zone 1 label because its predicted average clears 4 pCi/L outright — three-plus times the 0.4 pCi/L typical outdoors and above the 1.3 pCi/L most homes see. EPA's guidance doesn't change because of a Zone 1 label: test the house. What changes is the reason to not put it off in Smith County specifically.

Testing and mitigation in Smith 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 Kansas's state radon program

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

The methodology guide shows exactly which EPA and Census sources feed Smith County's numbers. If you're unsure why a low zone still deserves a test, the zone explainer covers that directly.