Brookings County, SD radon potential

Brookings County is mapped as Zone 1 - Highest Potential by EPA — meaning the county-wide average indoor level is predicted above 4 pCi/L. Nationally, Brookings County ranks higher in radon potential than 87% of rated counties (the 87th percentile).

How Brookings County compares

Brookings County, South Dakota is home to about 36,359 people across 792.217 square miles. Population density there runs about 46 people per square mile. Within its own EPA zone, Brookings County is bigger by population than 61% of the counties that share it. EPA's geology-based Region 8 groups Brookings County with 290 other counties nationally sharing its underlying rock and soil profile.

Zone vs. an actual test

Fixing a home becomes an EPA recommendation past 4 pCi/L, and that is precisely the side of the line Brookings County's Zone 1 prediction lands on, well above the roughly 1.3 pCi/L most US homes average. A Zone 1 rating means testing is worth doing sooner rather than later, but it is still county-wide average, not a reading for any single house — some homes in Brookings County will test well under the action level, and EPA's guidance is to test regardless of zone.

Next steps for a home in Brookings 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 South Dakota's state radon program

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

Where Brookings County's figures come from

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