Radon levels in Norfolk County, Massachusetts

LowEPA Zone 2

Predicted long-term basement average of 1.8 pCi/L (model estimate) across 39 ZIP codes - close to the US average of 1.8, close to the Massachusetts average of 1.8. Ranked #8 of 14 Massachusetts counties.

Test Norfolk County, MA once anyway - radon varies house to house

The predicted basement average here is 1.8 pCi/L, below the EPA's 2 pCi/L "consider fixing" threshold. That's good news for the area - but the EPA still recommends every home be tested, because foundation cracks, soil pockets and ventilation make one house very different from its neighbor. One inexpensive kit settles it.

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Predicted (model estimate). The pCi/L figures on this page are long-term area averages from a peer-reviewed national model built on millions of real radon tests (2001-2021). They describe the typical home in this area - not your home, which can be several times higher or lower. The EPA radon zone is a separate, 1993 county-level classification. How the numbers work.

1.8 ± 0.06

pCi/L predicted basement mean (model SD)

1.0 ± 0.06

pCi/L predicted upstairs (above-ground) mean

1.3-2.9

range of ZIP-level basement predictions in the county

What this means for Norfolk

The typical Norfolk County home is predicted below 2 pCi/L, the lowest band. That is the best case an area can show - but it describes the average house, and the ZIP-level predictions within the county still span 1.3 to 2.9 pCi/L.

Note that the EPA classifies Norfolk County as Zone 2 while the newer model predicts 1.8 pCi/L. The zone map predates two decades of test data; where they disagree, we grade on the model but show both. County figures weight each ZIP by its 2010 Census population, so they describe where people live rather than empty land.

Comparable Massachusetts counties: Bristol County (1.8), Plymouth County (1.8), Middlesex County (1.8), Berkshire County (1.7). The state's highest is Worcester County at 2.5 pCi/L.

ZIP codes in Norfolk County

Predicted basement and upstairs means by ZIP (model estimate). ZIPs whose land is mostly in this county.

ZIPBasementUpstairsGrade
021691.7 ± 0.060.9Low
021841.7 ± 0.061.0Low
023681.6 ± 0.061.1Low
020382.0 ± 0.041.4Moderate
024461.4 ± 0.070.7Low
020621.6 ± 0.051.0Low
021861.7 ± 0.060.7Low
020721.6 ± 0.051.3Low
020261.7 ± 0.061.1Low
024671.6 ± 0.060.8Low
020211.7 ± 0.061.1Low
024451.4 ± 0.050.7Low
024921.6 ± 0.050.8Low
021701.7 ± 0.070.7Low
020811.9 ± 0.051.1Low
021711.3 ± 0.060.7Low
020671.7 ± 0.051.3Low
020352.4 ± 0.071.1Moderate
020191.5 ± 0.051.3Low
024811.7 ± 0.060.9Low
021902.0 ± 0.051.1Low
020902.1 ± 0.070.9Moderate
021881.9 ± 0.060.9Low
021891.8 ± 0.061.0Low
020531.8 ± 0.051.3Low
020521.8 ± 0.051.1Low
020562.7 ± 0.071.2Moderate
020932.6 ± 0.071.3Moderate
023431.7 ± 0.061.2Low
024821.5 ± 0.071.2Low
024941.7 ± 0.070.8Low
021911.5 ± 0.070.9Low
027622.9 ± 0.071.1Moderate
020541.8 ± 0.061.2Low
020251.5 ± 0.080.9Low
020301.8 ± 0.051.1Low
023221.8 ± 0.041.1Low
020321.9 ± 0.071.1Low
020711.7 ± 0.051.0Low

If your test comes back at 4 pCi/L or higher

Mitigation is a routine job: a fan-driven pipe that vents soil gas from under the slab to above the roofline, typically $800-$2,500 installed (typical range; local quotes vary). Use certified professionals: EPA find-a-professional. Read the full mitigation guide.

Norfolk County radon questions

Is radon high in Norfolk County, Massachusetts?
Low. The model predicts a long-term basement average of 1.8 pCi/L in Norfolk County (close to the US average of 1.8 and close to the Massachusetts average of 1.8). That is below the EPA's 2 pCi/L "consider fixing" threshold, though individual homes still vary. Ranked 8 of 14 Massachusetts counties.
Should I test for radon in Norfolk County?
Yes, once. The EPA recommends testing every home regardless of area, and the model's ZIP-level predictions in Norfolk County already range from 1.3 to 2.9 pCi/L. A short-term kit costs little and settles the question for your house.
What does EPA Radon Zone 2 mean for Norfolk County?
Zone 2 - moderate potential (2-4 pCi/L). The zone map dates from 1993 and classifies whole counties. The newer model's predicted average of 1.8 pCi/L does not line up with Zone 2, which is common - the EPA itself says high-radon homes exist in every zone. Neither replaces a test of your own home.
How much does radon mitigation cost in Norfolk County?
A standard active sub-slab depressurization system typically runs $800-$2,500 installed nationally; Massachusetts quotes vary with foundation type (slab, crawlspace, basement), home size and local labor. Get two or three bids from certified mitigators listed by your state radon program or the EPA's find-a-professional page.

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