Mellette County, SD radon potential

EPA's own radon map rates Mellette County zone 2 - moderate potential, predicting a county-wide average indoor level between 2 and 4 pCi/L. Mellette County sits at the 34th percentile nationally for radon potential — above 34 of every 100 rated counties.

Where Mellette County sits nationally

Mellette County, South Dakota is home to about 1,834 people across 1,307.311 square miles. That works out to roughly 1 people per square mile. Within its own EPA zone, Mellette County is bigger by population than 2% of the counties that share it. Mellette County falls in EPA Radon Region 8, one of 291 counties nationally EPA assigns to that same geologic province.

What this actually means for a house in Mellette County

Mellette County's Zone 2 prediction clears the 1.3 pCi/L national indoor average without reaching EPA's own 4 pCi/L point for recommending a fix. Nothing about a Zone 2 label lowers the case for testing in Mellette County — EPA recommends it in every zone, moderate included.

If Mellette County tests above the action level

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 South Dakota's state radon program

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

Where Mellette County's figures come from

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