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How can you protect yourself from radon?

By Radon411 Editorial TeamUpdated How we research

Short answer

Test your home, because radon cannot be seen, smelled or tasted, and if the level is high, have a trained contractor install a radon reduction system and test again to confirm it worked. Then retest every two years, and if you smoke, stop, since smoking and radon together raise lung cancer risk.

Next step: a test is the only way to know your home's level. How to test your home

Start with a measurement in the lowest lived-in level: a of two to 90 days for a quick answer, or a of more than 90 days for the year-round average. If a first short-term result is high, take a followup test to be sure.

A confirmed high level is fixed by keeping radon out. The method primarily used is a vent pipe and fan that pulls radon from beneath the house and vents it outside; some systems cut radon by up to 99 percent, and most homes can be fixed for about the same cost as other common home repairs. Opening windows is only temporary, and sealing alone is not recommended.

Radon is much more likely to cause lung cancer in people who smoke. If you are building, radon-resistant features cost the builder less than mitigating later.

What to do next: order a test kit or book a measurement professional, then use the interpreter to read your result.

Protection in four steps

You can't see radon, and you can't smell it or taste it, so protection starts with a number. Testing is the only way to know if you and your family are at risk. After that, the steps follow the result.

How to protect yourself from radon
StepWhat to doWhy
1. TestTest the lowest lived-in level of your homeTesting is the only way to know your level
2. ConfirmTake a followup test to be sure before you fixA short-term test is less likely to show the year-round average
3. FixHave a trained contractor install a radon reduction systemSome systems cut radon by up to 99 percent
4. Keep checkingTest after the fix, then retest every two yearsTo be sure radon levels remain low

Testing is recommended for all homes below the third floor. See how to test for radon.

Step one: measure

Place the test in the lowest lived-in level of the home. A stays two days to 90 days, depending on the device; a stays more than 90 days and gives a better picture of the year-round average, because radon levels vary from day to day and season to season.

Flowchart of EPA's radon testing steps: take a short-term test; at or above 4 pCi/L follow up with a long-term or a second short-term test; then fix the home or consider fixing based on the result or the average of the two tests.
Read this figure as text

  1. 1Step 1: Take a short-term test.

    • Below 4 pCi/LEven if your test result is below 4 pCi/L, you may want to test again sometime in the future.
    • At or above 4 pCi/LIf your result is at or above 4 pCi/L, take a followup test to be sure.

  2. 2Step 2: Follow up with either a long-term test or a second short-term test.

    • Long-term testFor a better understanding of your year-round average radon level, take a long-term test.
    • Second short-term testIf you need results quickly, take a second short-term test. If your first short-term test result is more than twice EPA's 4 pCi/L action level, you should take a second short-term test immediately.

  3. 3Step 3: Decide whether to fix your home.

    • After a long-term testFix your home if your long-term test result is 4 pCi/L or more.
    • After a second short-term testConsider fixing your home if the average of your first and second test is at or above 4 pCi/L.
From a first short-term test to a follow-up, then to a decision to fix or consider fixing.

Step two: fix a high level

Methods that prevent radon from entering are the ones generally recommended. The one primarily used is a vent pipe and fan that pulls radon from beneath the house and vents it outside, and sealing foundation cracks and other openings makes it more effective. Most homes can be fixed for about the same cost as other common home repairs.

Cross-section of a house with a sub-slab depressurization system: soil gas drawn from beneath the slab into a suction point, up a vent pipe, through a fan outside the living space and out above the roofline.
Read this figure as text
Sub-slab depressurization system in a house cross-sectionGround levelLiving spaceBasement12345
  1. Soil gas drawn from beneath the slab
  2. Suction point through the slab
  3. Vent pipe
  4. Fan, outside the living space
  5. Discharge above the roofline
A soil suction system: radon is drawn from under the slab and vented above the roof.

Use a contractor trained to fix radon problems; many states require radon professionals to be licensed, certified or registered. The fan must run continuously for the system to work. See radon mitigation.

What does not protect you

Shortcuts that fall short
ShortcutThe problem
Opening windowsOnly a temporary approach: once windows, doors and vents are closed, radon most often returns to previous values within about 12 hours
Sealing cracks aloneBy itself, sealing has not been shown to lower radon levels significantly or consistently
Relying on a neighbor's resultRadon levels can vary greatly from home to home
Testing water before airIt is important to first test the air in the home

Lower your other risks too

Radon is much more likely to cause lung cancer in people who smoke, because radon and cigarette smoking act together. Stop smoking and lower your radon level to reduce your lung cancer risk. It's never too late: even levels below 4 pose some risk, and lowering your radon level reduces it.

Building or buying

Builders can construct new homes that resist radon entry, and the cost of including those features is typically less than the cost to mitigate the home later. A new home buyer may ask the builder about them, and ask for them if they are not provided. Every new home should still be tested after occupancy, even if it was built radon-resistant.

Questions about protecting yourself from radon

What is the best way to protect yourself from radon?

Test your home, and if the level is high, have a radon reduction system installed and test again to confirm it worked.

My neighbor's home tested low. Do I still need to test?

Yes. Radon levels can vary greatly from home to home, so only a test of your own home tells you your level.

Does opening windows protect you from radon?

Only for a while. Radon most often returns to previous levels within about 12 hours of closing windows, doors and vents.

How often should I retest to stay protected?

Retest every two years, and retest on a lower level if you start living there.

Is there a safe level of radon?

Even levels below 4 pCi/L pose some risk, and you can reduce your risk by lowering your radon level.

Does quitting smoking reduce radon risk?

Yes. Radon is much more likely to cause lung cancer in people who smoke, so stopping smoking and lowering radon both reduce the risk.

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