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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

Predicted
3 of 14counties in Zone 1, EPA's highest radon zone
Measured
By countyCDC publishes Massachusetts's test figures by county: 14 of 14 counties have one.
Your home
Test to knowNo area figure here is a reading of your home.
How to test this homeFind a certified tester

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 describes predicted potential across a whole county. It is not intended to determine whether any individual home should be tested, and homes with elevated levels occur in all three zones. EPA recommends testing every home regardless of zone, and testing is the only way to know the radon level in a specific building.

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.

Massachusetts, Counties

Massachusetts counties by EPA zone

Predicted

Massachusetts's radon map, then all 14 counties by the zone EPA predicts for each, highest reported share of tests at or above 4 pCi/L first. Each has its own report.

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.Predicted potential for each county, not a reading of any home. Homes with elevated levels of radon have been found in all three zones.

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

Radon Action Brief

National Radon Action MonthPre-sale

The radon brief for your Massachusetts county, in one dated file.

  • Your area's radon record, explained.
  • Your plan to test this week.
  • Fix costs and pros near you.

Save 64%Sale price: $8.99Price after the sale: $25Ends Jan 31Then $25

Get your Massachusetts county's BriefSee a free sample

Area data, not a test of the building.

What it means

Massachusetts, Questions

Questions about radon in Massachusetts

Common questions

9 questions, answered from the figures above

Is radon a problem in Massachusetts?

EPA's Map of Radon Zones places 3 of the 14 Massachusetts counties it classifies in Zone 1, the highest predicted potential, 10 in Zone 2 and 1 in Zone 3. An EPA radon zone describes predicted potential across a whole county. It is not intended to determine whether any individual home should be tested, and homes with elevated levels occur in all three zones. EPA recommends testing every home regardless of zone, and testing is the only way to know the radon level in a specific building.

Massachusetts on the radon mapRadon levels by state

Who does radon mitigation in Massachusetts?

Radon411's Massachusetts directory lists 5 radon businesses for testing, mitigation or both, each with the licensing list it was read from. EPA recommends having a qualified contractor fix a home with a radon problem, because lowering high radon levels takes technical knowledge and special skills, and some states require the work to be done by a licensed or certified professional.

How radon mitigation worksWhat mitigation costsRadon professionals in Massachusetts

How do I get a radon test in Massachusetts?

EPA says you can test your home yourself or hire a qualified radon test company, and that either approach takes only a small amount of time and effort. The Massachusetts radon program is the place to ask about certified testers and any test kit offer it runs.

How to test a homeFree and low-cost kits by stateMassachusetts radon program

Which Massachusetts counties are in EPA radon Zone 1?

3 counties are in Zone 1: Essex County, Middlesex County, Worcester County. Zone 1 is EPA's class for highest predicted potential, a predicted average indoor screening level greater than 4 pCi/L. A zone is a prediction for a county, not a measurement of any home.

Radon in Essex CountyRadon in Middlesex CountyRadon in Worcester County

Which Massachusetts counties have the highest radon?

14 of Massachusetts's 14 counties have an EPA radon zone published here. Radon411 will not rank counties on data it does not hold, and a zone is a prediction for an area rather than a measurement of any building.

What share of radon tests in Massachusetts are high?

CDC has published no statewide radon testing statistics for Massachusetts, so we cannot give a figure. Where CDC does publish one, the percentage describes radon tests reported to CDC, not homes.

Which EPA region is Massachusetts in?

Massachusetts is in EPA Region 1: New England.

Do I need to test my home in Massachusetts?

Yes, wherever you live in the state. Testing is the only way to know the radon level in a specific building. EPA recommends fixing a home when the radon level is 4 pCi/L or higher. EPA recommends considering a fix when the level is between 2 and 4 pCi/L.

Why does this page show coverage rather than one radon level for Massachusetts?

A statewide figure averages counties with very different geology and very different numbers of reported tests, so it hides more than it shows. The county report is the level at which the EPA zone, the geologic potential and the reported testing statistics are actually published, which is why the county table above links to every one of them.

If you own, buy, sell or rent

What these figures mean for each reader, with the guide that covers it

The zone counts on this page describe counties across Massachusetts. They are predictions for areas, and none of them measures your building.

Massachusetts in figures

The figures above, said in words

What the published data says about Massachusetts, in words. A zone and a share of tests describe an area, never the level in any one home.

    • Predicted

      Predicted

      EPA places 3 of Massachusetts's 14 counties in Zone 1, 10 in Zone 2 and 1 in Zone 3.

      The Zone 1 counties: Essex County, Middlesex County and Worcester County.

    • Compared

      Calculated by Radon411

      21% of Massachusetts's counties with a zone on file are in Zone 1, a smaller share than across all U.S. counties (34%). It is a share of counties, not of land, people or homes.

  • Reported tests

    Measured

    CDC has no statewide testing figure for Massachusetts on file here.

    14 of the 14 counties have a published county figure; the most tests in each one's latest year were reported for Middlesex County (75,220 tests over 2008 to 2017, laboratory), Worcester County (46,440 tests over 2008 to 2017, laboratory) and Norfolk County (39,205 tests over 2008 to 2017, laboratory).

Massachusetts's radon program is the Radon Unit, run by Department of Public Health; its contacts are under Local resources.

Products

Massachusetts, Products

Testing and mitigation products

Whatever the figures for Massachusetts show, only a test tells you about one home.

Test kits and monitors42

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Best radon monitors for Massachusetts homes, compared

Testing

5

Mitigation

3

Explore

Massachusetts, Next steps

What to do next

  1. LearnKnow what radon isWhat radon is, how it gets indoors, and why a county zone is not a reading for your home.Learn about radon
  2. TestTest the building you live inShort-term or long-term, where the device goes, and closed-house conditions.How to test
  3. FixBring a high level downHow a mitigation system works, and the retest that confirms it.How mitigation works
  4. Find a proHire a certified professionalMeasurement and mitigation professionals by state, with their certifications.Find a professional

Informational. Follow EPA guidance. EPA says all radon tests should be taken for a minimum of 48 hours, with windows and doors closed from 12 hours before a short-term test.