Bennett County, SD: EPA's radon zone, explained

EPA places Bennett County in Zone 2 - Moderate Potential — a predicted county-wide average indoor radon level between 2 and 4 pCi/L, based on the geology, soil and aerial radioactivity data behind EPA's national map. Nationally, Bennett County ranks higher in radon potential than 35% of rated counties (the 35th percentile).

Bennett County by the numbers

Bennett County, South Dakota is home to about 3,289 people across 1,184.642 square miles. That works out to roughly 3 people per square mile. By population, Bennett County is the 980th largest of every county sharing its EPA zone — the 5th percentile by population within that zone. Geologically, Bennett 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

Bennett County's predicted average falls between EPA's 4 pCi/L action level and the national indoor average of about 1.3 pCi/L (outdoor air runs roughly 0.4 pCi/L). A county-wide moderate average, like Bennett County's, can still hide a specific house well above or below it — testing is what actually answers the question.

Next steps for a home in Bennett County

For a Bennett County homeowner, the order is simple: test first, since a kit costs a small fraction of what mitigation would. Only if the result clears 4 pCi/L does a system — typically $800–$2,500, about $1,200 for a common install — become worth pricing out.

Find South Dakota's state radon program

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

Every figure on this page traces to EPA's own Map of Radon Zones and Census data, documented in the methodology guide. The guide to what a radon zone actually means covers why testing matters in every zone, not just Zone 1.