Is Hennepin County, MN a radon risk area?

EPA's own radon map rates Hennepin County zone 1 - highest potential, predicting a county-wide average indoor level above 4 pCi/L. Nationally, Hennepin County ranks higher in radon potential than 100% of rated counties (the 100th percentile).

Where Hennepin County sits nationally

About 1,273,334 people live in Hennepin County, Minnesota, spread over 554.02 square miles. Averaged across its land area, Hennepin County runs about 2,298 people per square mile. Rank 3 by population within its EPA zone puts Hennepin County at the 100th percentile among zone peers. EPA's geology-based Region 5 groups Hennepin County with 523 other counties nationally sharing its underlying rock and soil profile.

Why the zone isn't the answer by itself

Outdoor air nationally averages about 0.4 pCi/L, indoor air about 1.3 pCi/L — Hennepin County's Zone 1 prediction clears both of those and EPA's fix-it threshold besides. EPA's guidance doesn't change because of a Zone 1 label: test the house. What changes is the reason to not put it off in Hennepin County specifically.

Testing and mitigation in Hennepin County

Nothing about Hennepin County's EPA zone changes the mitigation number: $800–$2,500 nationally (around $1,200 typical), set by the house's foundation rather than the county it sits in — and only relevant once a test actually clears 4 pCi/L.

Find Minnesota's state radon program

Hennepin County's test kit answers today; a Airthings radon monitor keeps answering for Hennepin County over time. Affiliate link, RadonZoneCheck earns a commission there, at no extra cost to you. Use code RADONZONE-10OFF at checkout for 10% off.

More on how this number was built

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