Skip to content
RADON411
$5

County radon report

Get it

Locations and reports

Radon Levels in Delaware

3 counties · EPA Region 3: Mid-Atlantic

What this means for you

  • Your area: None of Delaware's 3 classified counties is in EPA Zone 1, the highest of its three radon zones. Zones are predictions for whole counties, and homes with elevated levels occur in all three zones.
  • Local tests: CDC publishes Delaware's radon test results by county. Open your county below to see its figures.
  • Your home: The only way to know your home’s level is to test it.
How to testFind a certified tester

pCi/L (picocuries per liter) is the unit radon is measured in. EPA recommends fixing a home at 4 pCi/L or above, its action level.

For Delaware, EPA's Map of Radon Zones places 0 of its 3 classified counties in Zone 1, highest predicted potential, a prediction for each county as a whole. Radon levels vary from home to home, so only a test measures the level in yours.

Predicted: EPA radon zone

3 of 3 counties classified

EPA classifies counties, not states. Of the 3 counties in Delaware with a zone, 1 is in Zone 2 and 2 in Zone 3.

  • Zone 2: Moderate predicted potential2 to 4 pCi/L1 of 3 counties · 33.3%
  • Zone 3: Lower predicted potentialless than 2 pCi/L2 of 3 counties · 66.7%

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.

This is a county-level geologic prediction. It is not a measurement of any address, and houses with elevated radon are found in all three zones.

Predicted: EPA Map of Radon Zones

Measured: tests reported to CDC

CDC publishes Delaware's radon test figures by county: 3 of its 3 counties have one. Each county's share is in the county list.

Delaware, In figures

Delaware in figures

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

    • Predicted

      Predicted

      EPA places 1 of Delaware's 3 counties in Zone 2 and 2 in Zone 3.

      No Delaware county is in Zone 1.

    • Compared

      Calculated by Radon411

      0% of Delaware'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 Delaware on file here.

    3 of the 3 counties have a published county figure; the most tests in each one's latest year were reported for New Castle County (9,184 in 2017), Kent County (1,222 in 2017) and Sussex County (329 in 2017).

Delaware's radon program is the Delaware Division of Public Health Radon Office, run by Delaware Division of Public Health; its contacts are under Local resources.

Delaware, Counties

Delaware counties by EPA zone

Predicted

All 3 counties, by the zone EPA predicts for each. Every county has its own report.

Delaware, Local resources

Local resources in Delaware

Who to ask in Delaware: the state's radon program, test kits and professionals.

Delaware Division of Public Health Radon Office

Delaware Division of Public Health

Delaware’s radon program answers questions about testing, mitigation and the rules where you live.

Phone
1-800-464-HELP
Visit the program's page(opens in a new tab)

Test kits

The program says: Delaware Residents click HERE for your free radon test kit.

Free and low-cost kitsCompare kits

Radon professionals

25 professionals are listed in Delaware.

Professionals in Delaware

Delaware, Questions

Questions about radon in Delaware

Common questions8 questions, answered from the figures above

Is radon a problem in Delaware?

EPA's Map of Radon Zones places 0 of the 3 Delaware counties it classifies in Zone 1, the highest predicted potential, 1 in Zone 2 and 2 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.

Delaware on the radon mapRadon levels by state

How do I get a radon test in Delaware?

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 Delaware 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 stateDelaware radon program

Who does radon mitigation in Delaware?

Radon411's Delaware directory lists 25 certified radon companies. 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 Delaware

Which Delaware counties have the highest radon?

3 of Delaware's 3 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 Delaware are high?

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

Delaware is in EPA Region 3: Mid-Atlantic.

Do I need to test my home in Delaware?

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 Delaware?

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.

What these figures mean if you own, buy, sell or rent

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

  • If you own your home

    Test the lowest lived-in level; a short-term kit screens in days, a long-term kit reflects the year.

    How to test a home

  • If you are buying

    Ask for past results and any system's post-mitigation test, and test during the sale.

    Buying a house: radon guide

  • If you are selling

    Testing before you list puts the timing in your hands; disclosure rules differ by state.

    Selling a house: radon guide

  • If you rent, or rent out a home

    A tenant can test; a fix is the owner's to make, and duties differ by state.

    Radon in rental homes

How long a test has to run, under what conditions, and what EPA says a result means: the testing standard, in full.

Delaware, Products

Testing and mitigation products

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

Testing

Mitigation

Delaware, Keep reading

Keep reading

Looking for another state? Browse all state radon reports.

Delaware / Next steps

What to do next

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.