Nicollet County, MN: EPA's radon zone, explained

Nicollet County is mapped as Zone 1 - Highest Potential by EPA — meaning the county-wide average indoor level is predicted above 4 pCi/L. That puts Nicollet County in the 86th percentile nationally for radon potential — higher than 86% of the counties EPA has rated.

How Nicollet County compares

Nicollet County, Minnesota is home to about 34,493 people across 448.504 square miles. That works out to roughly 77 people per square mile. By population, Nicollet County is the 427th largest of every county sharing its EPA zone — the 60th percentile by population within that zone. Nicollet County falls in EPA Radon Region 5, one of 524 counties nationally EPA assigns to that same geologic province.

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 Nicollet 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 Nicollet County will test well under the action level, and EPA's guidance is to test regardless of zone.

Next steps for a home in Nicollet County

For a Nicollet 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 Minnesota's state radon program

For Nicollet County, an ongoing number beats a one-time test - a Airthings radon monitor tracks Nicollet 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 Nicollet 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.