Sibley County, MN radon potential

Sibley County is mapped as Zone 1 - Highest Potential by EPA — meaning the county-wide average indoor level is predicted above 4 pCi/L. Sibley County sits at the 79th percentile nationally for radon potential — above 79 of every 100 rated counties.

Where Sibley County sits nationally

Sibley County, Minnesota is home to about 15,194 people across 588.967 square miles. Averaged across its land area, Sibley County runs about 26 people per square mile. Within its own EPA zone, Sibley County is bigger by population than 38% of the counties that share it. Geologically, Sibley County is grouped into EPA Region 5 alongside 523 other counties that share its rock and soil setting.

Zone vs. an actual test

Sibley 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. That doesn't mean every Sibley 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 Sibley 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 Minnesota's state radon program

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

Sibley County's zone, rank and region all trace back to named EPA and Census sources — the methodology guide lists exactly which ones. The guide to what a radon zone actually means covers why testing matters in every zone, not just Zone 1.