Perkins County, SD: EPA's radon zone, explained
EPA's own radon map rates Perkins County zone 1 - highest potential, predicting a county-wide average indoor level above 4 pCi/L. Nationally, Perkins County ranks higher in radon potential than 68% of rated counties (the 68th percentile).
Where Perkins County sits nationally
Perkins County, South Dakota is home to about 2,832 people across 2,870.46 square miles. Population density there runs about 1 people per square mile. By population, Perkins County is the 987th largest of every county sharing its EPA zone — the 7th percentile by population within that zone. Perkins 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 Perkins County
Perkins 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. Being in Zone 1 raises the odds Perkins County homes test above the action level, but it does not mean any specific house does — EPA recommends every home be tested, in every zone, because the only way to know is to test.
Testing and mitigation in Perkins County
For a Perkins 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 Perkins County, an ongoing number beats a one-time test - a Airthings radon monitor tracks Perkins County's levels over time. RadonZoneCheck earns a commission there, at no extra cost to you. RADONZONE-10OFF at checkout knocks 10% off.
Where Perkins County's figures come from
Perkins County's zone, rank and region all trace back to named EPA and Census sources — the methodology guide lists exactly which ones. If you're unsure why a low zone still deserves a test, the zone explainer covers that directly.