31%tests ≥ 4 pCi/L
1,179tests on record
2.1median pCi/L
Zone 2EPA zone (1993 prediction)

Test results in Merrimack County

ResultShareEPA guidance
Below 2 pCi/L46%Below EPA's levels
2 to 4 pCi/L22%Consider fixing
4 pCi/L or more31%EPA recommends fixing

What the data shows

Where Merrimack County sits among New Hampshire's 10 counties with dataEach dot is a county's share of tests at or above 4 pCi/L · Radon test results from laboratories, 2008–2017
0%10%20%30%40%50%

How Merrimack County compares

Merrimack County ranks 5 of 7 among its neighboursShare of tests at or above 4 pCi/L · Radon test results from laboratories, 2008–2017 · whisker: 95% range
Strafford County43%Rockingham County42%Hillsborough County34%Belknap County32%Merrimack County31%Grafton County26%Sullivan County25%New Hampshire 35%
Data table
AreaTests ≥ 4 pCi/LTests
Strafford County43%870
Rockingham County42%4,077
Hillsborough County34%5,528
Belknap County32%385
Merrimack County31%1,179
Grafton County26%1,579
Sullivan County25%251
New Hampshire (10 counties)35%15,608

Same source as Merrimack County.

What it means for your home

About 1 in 3 results in Merrimack County were at or above 4 pCi/L, where the EPA recommends a fix. Only a test shows your own home's level.

Levels in pCi/L from the EPA. The WHO reference level is 100 Bq/m³, about 2.7 pCi/L.

Test your home

Start with a short-term test (2–90 days) and confirm a result of 4 pCi/L or more with a second test. EPA guide

Sponsored: we earn a commission on purchases through these links. We haven't tested Airthings monitors yet.

Prefer a digital monitor? See Airthings radon monitors, or enter code radonbycounty-10OFF at their discount store for 10% off.

Fixing high radon

No local job records yet. National range: $800–$2,500, average $1,200 (EPA, 2003). Cost guide →

About this data

Source: Radon test results from laboratories (CDC Environmental Public Health Tracking Network). Period: 2008–2017. Tests: 1,179. Read the methodology →

These are voluntary and real-estate tests, not a random sample of homes, so they describe tested homes rather than every home.

About this page

Published by Ray Roman, editor of Radon by County. Figures are loaded from the cited source and spot-checked against it. Editorial policy · About us