Is Somerset County, NJ a radon risk area?

Somerset County is mapped as Zone 1 - Highest Potential by EPA — meaning the county-wide average indoor level is predicted above 4 pCi/L. Somerset County sits at the 98th percentile nationally for radon potential — above 98 of every 100 rated counties.

How Somerset County compares

About 357,467 people live in Somerset County, New Jersey, spread over 301.873 square miles. That works out to roughly 1,184 people per square mile. Rank 66 by population within its EPA zone puts Somerset County at the 94th percentile among zone peers. EPA's geology-based Region 2 groups Somerset County with 82 other counties nationally sharing its underlying rock and soil profile.

Why the zone isn't the answer by itself

Where the national indoor average runs about 1.3 pCi/L, Somerset County's Zone 1 rating puts its predicted county average above EPA's 4 pCi/L action level itself. 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 Somerset County specifically.

Next steps for a home in Somerset County

Nothing about Somerset 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 New Jersey's state radon program

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

More on how this number was built

The methodology guide shows exactly which EPA and Census sources feed Somerset County's numbers. Whatever zone Somerset County carries, the zone explainer covers what it does and doesn't tell you about any one house.