Corson County, SD radon potential

EPA's own radon map rates Corson County zone 1 - highest potential, predicting a county-wide average indoor level above 4 pCi/L. That puts Corson County in the 69th percentile nationally for radon potential — higher than 69% of the counties EPA has rated.

How Corson County compares

Corson County, South Dakota is home to about 3,747 people across 2,469.694 square miles. That works out to roughly 2 people per square mile. Within its own EPA zone, Corson County is bigger by population than 10% of the counties that share it. Geologically, Corson County is grouped into EPA Region 8 alongside 290 other counties that share its rock and soil setting.

Why the zone isn't the answer by itself

Outdoor air nationally averages about 0.4 pCi/L, indoor air about 1.3 pCi/L — Corson County's Zone 1 prediction clears both of those and EPA's fix-it threshold besides. That doesn't mean every Corson County house tests high — a zone is a county-wide prediction, never a single-home reading — but it's a reason to test sooner rather than let it wait.

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

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