What EPA's radon map says about Dukes County

EPA's own radon map rates Dukes County zone 2 - moderate potential, predicting a county-wide average indoor level between 2 and 4 pCi/L. Nationally, Dukes County ranks higher in radon potential than 47% of rated counties (the 47th percentile).

How Dukes County compares

About 21,061 people live in Dukes County, Massachusetts, spread over 103.202 square miles. Population density there runs about 204 people per square mile. Among counties sharing Dukes County's EPA zone, it outranks 41% of them by population. EPA's geology-based Region 1 groups Dukes County with 58 other counties nationally sharing its underlying rock and soil profile.

Zone vs. an actual test

Call it a middle case: above the 1.3 pCi/L most US homes average, below the 4 pCi/L line EPA uses to recommend mitigation — that's Dukes County's Zone 2 prediction. Middle-of-the-pack doesn't mean risk-free for any one Dukes County address — a moderate county average still leaves individual homes to test either side of it.

If Dukes County tests above the action level

Mitigation cost doesn't depend on Dukes County's zone — it depends on the house's foundation. A typical system runs $800–$2,500 (about $1,200 typical), and testing first is what tells you whether that's needed at all.

Find Massachusetts's state radon program

Dukes County's test kit answers today; a Airthings radon monitor keeps answering for Dukes 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 Dukes County's numbers. If you're unsure why a low zone still deserves a test, the zone explainer covers that directly.