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Massachusetts Radon Map and Levels by County

Massachusetts's counties span all three EPA radon zones. Homes with elevated levels occur in all three zones, so only a test measures yours.

Data checked By Radon411Methodology

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  • Share at 4+ pCi/L

    23.6%

    12.2 pts below U.S.

    Massachusetts
    23.6%
    U.S.
    35.8%

    248,798 tests across 14 counties, 2007 to 2016

  • Rank among states

    31 of 47

    Middle of the states

    Massachusetts
    23.6%
    North Dakota
    58.7%

    By share, every state pooled the same way, 2007 to 2016

  • Counties in EPA Zone 1

    3 of 14

    Some at highest potential

    Zone 1
    3
    Zone 2
    10

    Most counties sit in Zone 2; Zone 1 is the highest potential

  • Highest county

    33.3%

    Worcester County

    Worcester
    33.3%
    Nantucket
    5.0%

    Counties with 30+ tests, 2007 to 2016

Read a result for Massachusetts

Starts at EPA's action level

4.0pCi/L

EPA’s own thresholds; the figures are the area’s, never this home’s.

EPA’s reading of 4.0 pCi/L

At or above 4 pCi/L

  1. Under 20 to 1.9 pCi/L
  2. 2 to 4consider a fix
  3. 4 and aboveEPA says fix it

This result is at or above 4 pCi/L. EPA recommends fixing a home when the radon level is 4 pCi/L or higher. 23.6% of Massachusetts's reported tests reached 4 pCi/L, 2007 to 2016.

Interpret this readingWhat a fix costs

The data

Massachusetts, At a glance

Massachusetts at a glance

Predicted: EPA radon zone

14 of 14 counties classified

EPA classifies counties, not states. Of the 14 counties in Massachusetts with a zone, 3 are in Zone 1, 10 in Zone 2 and 1 in Zone 3.

  • Zone 1: Highest predicted potentialgreater than 4 pCi/L3 of 14 counties · 21.4%
  • Zone 2: Moderate predicted potential2 to 4 pCi/L10 of 14 counties · 71.4%
  • Zone 3: Lower predicted potentialless than 2 pCi/L1 of 14 counties · 7.1%

An EPA radon zone predicts a whole county. It is not intended to determine whether any individual home should be tested: homes with elevated levels occur in all three zones, and EPA recommends testing every home regardless of zone.

Predicted: EPA Map of Radon Zones

Measured: tests reported to CDC

CDC test figures, county by county

CDC publishes Massachusetts's radon test figures by county: 14 of its 14 counties have one. Each one's share is in the county list.

How to read these figures

Massachusetts, Compared

Massachusetts radon figures, compared

Calculated by Radon411
Massachusetts, 2007 to 2016, laboratory
23.6%
of 248,798 tests at or above 4 pCi/L, pooled
Against the U.S.
−12.2points
35.8% pooled
Rank among the states
31 of 47
1 is the highest share
Counties with 30 or more tests
14
Highest
33.3%
Worcester County
Lowest
5.0%
Nantucket County

About 2 in 10 of the 248,798 tests reported for Massachusetts over the 2007 to 2016 laboratory totals came back at or above 4 pCi/L (23.6%, 14 counties pooled). That is 31st of 47 states with county figures for the period; Georgia (23.9%) above it and Rhode Island (23.5%) below.

By band, 1 county at 30% to 50%, 10 counties at 15% to 30%, 3 counties at 5% to 15%. Its 14 counties with 30 or more tests run from 5.0% in Nantucket County to 33.3% in Worcester County; in 0 of them half or more of the reported tests reached 4 pCi/L.

EPA's 1993 map puts 3 of its 14 classified counties in Zone 1; against that, 23.6% of the tests reported since reached 4 pCi/L. The national pool for the same period is 35.8%, so Massachusetts runs 12.2 points below the country.

Across its 4 overlapping ten-year totals, the share went from 23.0% (2005 to 2014) to 23.8% (2008 to 2017), within 2 points, with 2008 to 2017 the highest at 23.8%.

Massachusetts ranked among 47 states by pooled share of tests at or above 4 pCi/L, 2007 to 2016, laboratory
StateRankCountiesTestsAt or above 4 pCi/L
Oregon26 of 473422,26126.3%
Washington27 of 47387,88325.5%
New York28 of 476292,76124.9%
Maryland29 of 472444,23224.4%
Georgia30 of 4713729,45523.9%
Massachusetts31 of 4714248,79823.6%
Rhode Island32 of 47536,35723.5%
North Carolina33 of 479970,56623.2%
Nevada34 of 471610,68422.9%
Arkansas35 of 476068722.7%
Florida36 of 476246,50822.7%
Massachusetts' highest counties with 30 or more tests, by share at or above 4 pCi/L, 2007 to 2016, laboratory
CountyRankTestsAt or above 4 pCi/L
Worcester County1 of 1449,36033.3%
Essex County2 of 1421,58128.6%
Berkshire County3 of 141,22626.2%
Bristol County4 of 1414,11723.0%
Middlesex County5 of 1480,57121.8%
Franklin County6 of 1485420.8%
Norfolk County7 of 1441,38520.8%
Barnstable County8 of 146,93220.1%
Hampshire County9 of 142,57718.2%
Plymouth County10 of 1416,91816.9%
Massachusetts' counties with 30 or more tests, by their own share at or above 4 pCi/L, 2007 to 2016, laboratory
ShareCountiesTheir testsFor example
50% or more00None
30% to 50%149,360Worcester County
15% to 30%10186,491Essex County, Berkshire County, Bristol County
5% to 15%312,947Hampden County, Suffolk County, Nantucket County
Under 5%00None
Massachusetts ten-year laboratory totals, pooled, against the United States
PeriodCountiesTestsAt or above 4 pCi/LUnited StatesChange from the row before
2008 to 201714234,15223.8%35.7%+0.2 points
2007 to 201614248,79823.6%35.8%+0.2 points
2006 to 201514240,29123.4%36.3%+0.4 points
2005 to 201414232,75923.0%36.0%First on file

Pooled shares: Radon411's sum of CDC's county counts for one period. CDC publishes no state or national figure.

Massachusetts, Counties

Massachusetts counties by EPA zone

Predicted

All 14 counties, grouped by the zone EPA predicts and ordered by their reported share at or above 4 pCi/L, under Massachusetts's map. Each county has a page of its own.

Massachusetts radon map by county: EPA radon zones. Map of Massachusetts's 14 counties shaded by EPA radon zone: Zone 1 in red-orange, Zone 2 in amber, Zone 3 in pale sand. 3 in Zone 1, 10 in Zone 2, 1 in Zone 3.
Massachusetts radon map by countyEPA radon zones for Massachusetts's counties: 3 counties in Zone 1, 10 counties in Zone 2, 1 county in Zone 3.A prediction for each county, not a reading of any home; elevated homes occur in all three zones.

The 12 highest in Massachusetts, 2007 to 2016

Zone 1: highest predicted potential3

Local help

Massachusetts, Local resources

Local resources in Massachusetts

Who to ask in Massachusetts: its radon program, test kits and professionals.

What Massachusetts's program says
Phone
(800) 723-6695
Email
DPHIAQ.radon@mass.gov

What it means

Massachusetts, Questions

Questions about radon in Massachusetts

Is radon a problem in Massachusetts?

Of the 14 counties in Massachusetts that EPA's Map of Radon Zones classifies, 3 carry Zone 1 (the highest predicted potential), 10 Zone 2 and 1 Zone 3. Pooled from 14 counties, 23.6% of the 248,798 radon tests reported to CDC over the 2007 to 2016 laboratory totals were at or above 4 pCi/L, 31st of 47 states.

Who does radon mitigation in Massachusetts?

5 radon businesses are listed for Massachusetts, for testing, mitigation or both; each listing names the licensing list it was read from.

Which Massachusetts counties are in EPA radon Zone 1?

Zone 1 holds 3 counties in Massachusetts: Essex County, Middlesex County, Worcester County.

Which Massachusetts counties have the highest radon?

Worcester County 33.3% (49,360 tests) leads Massachusetts by the share of reported tests at or above 4 pCi/L, 2007 to 2016, laboratory, then Essex County 28.6% (21,581 tests), Berkshire County 26.2% (1,226 tests), Bristol County 23.0% (14,117 tests), Middlesex County 21.8% (80,571 tests).

Which EPA region is Massachusetts in?

Massachusetts is in EPA Region 1: New England.

Products

Massachusetts, Products

Testing a home in Massachusetts

23.6% of the 248,798 tests reported to CDC for Massachusetts over the 2007 to 2016 laboratory totals reached 4 pCi/L: a short-term kit (2 to 90 days) gives a first answer in days, a long-term test the year-round average. A short-term kit (2 to 90 days) is the quick first check for a home in Massachusetts; a long-term test tells the year-round average.

Test kits and monitors3

See every kit and monitor

Best radon monitors for Massachusetts homes, compared

Explore

Cities in Massachusetts with their own page

Radon data is published by county, not by city. Each city page sets the figures of the counties the city lies in side by side.