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Connecticut Radon Map and Levels by County

Connecticut'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
4 of 8counties in Zone 1, EPA's highest radon zone
Measured
By countyCDC publishes Connecticut's test figures by county: 8 of 8 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

Connecticut, At a glance

Connecticut at a glance

Predicted: EPA radon zone

8 of 8 counties classified

EPA classifies counties, not states. Of the 8 counties in Connecticut with a zone, 4 are in Zone 1, 3 in Zone 2 and 1 in Zone 3.

  • Zone 1: Highest predicted potentialgreater than 4 pCi/L4 of 8 counties · 50.0%
  • Zone 2: Moderate predicted potential2 to 4 pCi/L3 of 8 counties · 37.5%
  • Zone 3: Lower predicted potentialless than 2 pCi/L1 of 8 counties · 12.5%

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 Connecticut's radon test figures by county: 8 of its 8 counties have one. Each one's share is in the county list.

Connecticut, Counties

Connecticut counties by EPA zone

Predicted

Connecticut's radon map, then all 8 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.

Connecticut radon map by county: EPA radon zones. Map of Connecticut's 8 counties shaded by EPA radon zone: Zone 1 in red-orange, Zone 2 in amber, Zone 3 in pale sand. 4 in Zone 1, 3 in Zone 2, 1 in Zone 3.
Connecticut radon map by countyEPA radon zones for Connecticut's counties: 4 counties in Zone 1, 3 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.

Local help

Connecticut, Local resources

Local resources in Connecticut

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

What Connecticut's program says
Phone
(860) 509-7300
Email
DPH.RadonReports@ct.gov
Licensing of radon professionals
The State of Connecticut does not license or otherwise certify radon professionals, however, the Radon Program maintains lists of nationally certified professionals...

Radon Action Brief

National Radon Action MonthPre-sale

The radon brief for your Connecticut 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 Connecticut county's BriefSee a free sample

Area data, not a test of the building.

What it means

Connecticut, Questions

Questions about radon in Connecticut

Common questions

9 questions, answered from the figures above

Is radon a problem in Connecticut?

EPA's Map of Radon Zones places 4 of the 8 Connecticut counties it classifies in Zone 1, the highest predicted potential, 3 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.

Connecticut on the radon mapRadon levels by state

Who does radon mitigation in Connecticut?

Radon411's Connecticut directory lists 71 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 Connecticut

Which Connecticut counties are in EPA radon Zone 1?

4 counties are in Zone 1: Fairfield County, Middlesex County, New Haven County, New London 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 Fairfield CountyRadon in Middlesex CountyRadon in New Haven County

How do I get a radon test in Connecticut?

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 Connecticut 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 stateConnecticut radon program

Which Connecticut counties have the highest radon?

8 of Connecticut's 8 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 Connecticut are high?

CDC has published no statewide radon testing statistics for Connecticut, 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 Connecticut in?

Connecticut is in EPA Region 1: New England.

Do I need to test my home in Connecticut?

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 Connecticut?

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 Connecticut. They are predictions for areas, and none of them measures your building.

Connecticut in figures

The figures above, said in words

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

    • Predicted

      Predicted

      EPA places 4 of Connecticut's 8 counties in Zone 1, 3 in Zone 2 and 1 in Zone 3.

      Zone 1 counties, A to Z, begin with Fairfield County, Middlesex County and New Haven County; the county section below lists all 4.

    • Compared

      Calculated by Radon411

      50% of Connecticut's counties with a zone on file are in Zone 1, a larger 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 Connecticut on file here.

    8 of the 8 counties have a published county figure; the most tests in each one's latest year were reported for Fairfield County (2,784 tests in 2019), New Haven County (1,007 tests in 2019) and Hartford County (606 tests in 2019).

  • Local record

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

    One city has a page setting the figures of the counties it lies in side by side: Stamford.

Products

Connecticut, Products

Testing and mitigation products

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

Test kits and monitors42

See all products

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Best radon monitors for Connecticut homes, compared

Testing

5

Mitigation

3

Explore

Cities in Connecticut 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.

Connecticut, 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.