Is Coos County, NH a radon risk area?

EPA's own radon map rates Coos County zone 2 - moderate potential, predicting a county-wide average indoor level between 2 and 4 pCi/L. Nationally, Coos County ranks higher in radon potential than 51% of rated counties (the 51st percentile).

How Coos County compares

About 31,094 people live in Coos County, New Hampshire, spread over 1,794.574 square miles. That works out to roughly 17 people per square mile. Rank 476 by population within its EPA zone puts Coos County at the 54th percentile among zone peers. EPA's geology-based Region 1 groups Coos County with 58 other counties nationally sharing its underlying rock and soil profile.

Zone vs. an actual test

Neither at the 4 pCi/L action level nor down at the roughly 1.3 pCi/L national indoor norm, Coos County's Zone 2 prediction lands in the gap between the two. Coos County's Zone 2 rating sits in the middle nationally; EPA's guidance is unchanged by that — test every home regardless of its zone.

If Coos County tests above the action level

Nothing about Coos 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 Hampshire's state radon program

Coos County's test kit answers today; a Airthings radon monitor keeps answering for Coos 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

Coos County's zone, rank and region all trace back to named EPA and Census sources — the methodology guide lists exactly which ones. If you're unsure why a low zone still deserves a test, the zone explainer covers that directly.