Facts About Radon Gas Testing

radon gas testing
Do you need to check for radon gas?. © Big Stock Photo

Radon gas is a colorless, odorless, tasteless radioactive gas that's formed during the natural breakdown of uranium in soil, rock, and water. Radon exits the ground and can seep into your home through cracks and holes in the foundation. Radon gas can also contaminate well water.

Health officials have determined that radon gas is a carcinogen that can cause lung cancer. Studies show that radon is more of a risk to smokers, but nonsmokers have a slightly elevated chance of developing lung cancer when radon levels in the home are high.

The only way to find out if your house contains radon gas is to perform radon tests.

EPA Radon Gas Studies

The EPA offers a look at what they believe to be the risks of radon at different concentrations for 1,000 people who smoked and were consistently exposed to a certain level of radon during their lifetimes.

Radon Risks for Smokers

  • With exposure to 10 pCi/L, about 71 would get cancer, equal to 100 times the risk of dying in a home fire.
  • With exposure to 4 pCi/L, about 29 would get cancer, equal to 100 times the risk of dying in a plane crash.

Radon Risks for Non-Smokers:

  • With exposure to 8 pCi/L, about 3 would get cancer, equal to 10 times the risk of dying in a plane crash.
  • With exposure to 4 pCi/L, about 2 would get cancer, equal to the risk of drowning.

Acceptable Radon Gas Levels

The Environmental Protection Agency, EPA, recommends you install a system to reduce radon gas in your home if the level of gas is 4 picocuries of radon per liter (pCi/L) or higher.

Facts About Radon Gas

  • There are no average radon levels for a specific city, state, or region.
  • Houses without basements are as much at risk of radon contamination as houses with basements.
  • It doesn't matter if your neighbor's radon test was low or high, results for your home may be completely different.

    Radon Gas Testing Methods

    There are two basic types of radon gas testing devices, passive and active. You can order a radon test kit and set it up yourself or you can hire a professional to perform the test.

    Passive Radon Gas Testing Devices

    • Do not need power to function.​
    • Include charcoal canisters, alpha-track detectors, and charcoal liquid scintillation devices that are exposed to the air in your home for a specific amount of time and are then sent to a laboratory for analysis.

    Active Radon Gas Testing Devices

    • Require power to function.
    • Continuously measure and record radon in the air, making radon spikes and dips more apparent.
    • Include continuous working level monitors and continuous radon monitors.
    • May include anti-interference features that reveal if the unit is moved during testing.
    • Generally considered to be more reliable than passive radon devices.​
    • Normally used only by home inspectors and air quality professionals.

    How Long Should You Test for Radon Gas?

    Long-term radon tests take more than 90 days but provide an accurate picture of the average amount of radon in your home. Since time is an issue, home buyers usually perform short term radon with either an active or passive testing device.

    Most short-term radon tests are completed in 48 to 96 hours.

    How To Test for Radon

    The EPA recommends that you perform radon tests on the lowest level of the home that could be used for living space without doing renovations.

    • Choose a room that is used regularly, but do not use the kitchen, bathroom, laundry room or a hallway.
    • Sometimes two devices are used simultaneously or two 48-hour tests are done back-to-back to help establish average radon levels and to verify that devices are working properly.
    • Keep windows and doors in the tested room shut except for normal entry and exit. For tests lasting less than four days, make sure windows and outside doors are closed for at least 12 hours before beginning.
    • Do not do short-term radon tests during times of high humidity, severe storms, or when winds are high.
    • Place the testing device at least 20 inches above the floor so that it is out of drafts and high humidity and will not be disturbed.
    • Follow the manufacturer's instructions to record starting and ending times. Reseal the tester package and return it to the lab for analysis.

    If you use an active device, the tester will give you instructions about what you should and should not do during the test.

    If Radon Levels Are Too High

    About 0.4 pCi/L of radon is found in the outside air and the average indoor radon level is about 1.3 pCi/L. The EPA recommends you use mitigation techniques to reduce indoor radon if levels in your home are above 4 pCi/L (or 0.02 working levels [WL] if your lab uses that reporting method.)

    Edited by Elizabeth Weintraub. At the time of writing, Elizabeth Weintraub, CalBRE #00697006, is a Broker-Associate at Lyon Real Estate in Sacramento, California.

    Radon levels can usually be lowered using a process called mitigation, a term that means to moderate something or make it less severe. Some radon mitigation methods prevent radon from entering your home and others reduce radon levels after the gas is there.

    The EPA recommends you use mitigation techniques to reduce indoor radon if levels in your home are above 4 pCi/L (or 0.02 working levels [WL] if your lab uses that reporting method).

    Common Radon Mitigation Methods

    Soil Suction

    A mitigation system draws radon from beneath the house and vents it away from the house through pipes.

    Sealing Cracks & Openings

    Sealing alone doesn't usually lower radon levels, but it can limit the flow of radon into a home and reduce the loss of air that's been heated or cooled.

    House Pressurization

    This method uses a fan to create pressure differences that help keep radon from entering the house.

    Heat Recovery Ventilator (HRV)

    Installed to increase ventilation, HRV uses the heated or cooled air being exhausted to warm or cool the incoming air. This type of system is most effective when used to ventilate only the basement of a house. Heating and cooling costs will likely rise when an HRV system is in place.

    Eliminating Radon in Water

    Use this type of system if you've determined that your private water supply is your home's source of radon.

    • Point-of-entry treatments use charcoal filters or aeration devices to remove radon from water before it enters your home.
    • Point-of-use devices remove radon at the tap, but they do nothing to reduce radon in unfiltered taps, such as your tubs, showers, and laundry areas, so radon in the air may remain high.

    Radon Mitigation for Existing Homes

    Your radon mitigation contractor can offer complete details about different types of radon reduction systems and will be in a better position to recommend the "best" system for your house after determining how radon is entering your home.

    Costs vary, but most systems can be installed for $1,000-$3,000.

    Radon Mitigation for New Homes

    If you're building a new home, now is the time to install a radon reduction system. The cost is far less than fitting a system after the home is built, and having the system in place will help the home's resale value.

    The EPA offers important advice to help you find a qualified radon service professional.

    If you are buying a home, be sure to include a radon contingency to your offer to purchase, stating the maximum level of radon that is acceptable to you. If tested levels are above that figure, you should have the right to back out of the contract with no penalties. Many standard forms contain a radon contingency addendum that can be added to your offer to purchase.

    Edited by Elizabeth Weintraub. At the time of writing, Elizabeth Weintraub, CalBRE #00697006, is a Broker-Associate at Lyon Real Estate in Sacramento, California.

    Radon levels can usually be lowered using a process called mitigation, a term that means to moderate something or make it less severe. Some radon mitigation methods prevent radon from entering your home and others reduce radon levels after the gas has entered.

    The EPA recommends you use mitigation techniques to reduce indoor radon if levels in your home are above 4 pCi/L (or 0.02 working levels [WL] if your lab uses that reporting method).

    Common Radon Mitigation Methods

    Soil Suction

    Draws radon from beneath the house and vents it away from the house through pipes.

    Sealing Cracks & Openings

    Sealing alone doesn't usually lower radon levels, but it can limit the flow of radon into a home and reduce the loss of air that's been conditioned, so it helps make other types of reduction techniques more effective.

    House Pressurization

    This method uses a fan to create pressure differences that help keep radon from entering the house.

    Heat Recovery Ventilator (HRV)

    Installed to increase ventilation, HRV uses the heated or cooled air being exhausted to warm or cool the incoming air. This type of system is most effective when used to ventilate only the basement of a house. Heating and cooling costs will likely rise when this type of system is in place.

    Eliminating Radon in Water

    If you've determined that your private water supply is your home's source of radon, it can be fixed.

    • Point-of-entry treatments use charcoal filters or aeration devices to remove radon from water before it enters your home.
    • Point-of-use devices remove radon at the tap, so you won't ingest it. They do nothing to reduce radon in unfiltered taps, such as your tubs, showers, and laundry areas, so radon in the air may remain high.

      Radon Mitigation for Existing Homes

      Your mitigation contractor can offer complete details about different types of radon reduction systems. After performing tests to determine how radon is entering your home the contractor will be in a better position to recommend the "best" system for your house. Costs vary, but most systems can be installed for $1,000-$2,500.

      Radon Mitigation for New Homes

      If you're building a new home, now is the time to install a radon reduction system. The cost is far less than fitting a system after the home is built, and having the system in place will be a good selling point later.

      The EPA offers important advice to help you find a qualified radon service professional.

      Edited by Elizabeth Weintraub. At the time of writing, Elizabeth Weintraub, CalBRE #00697006, is a Broker-Associate at Lyon Real Estate in Sacramento, California.

      If you are buying a home, be sure to include a radon contingency in your offer to purchase, stating the maximum level of radon that is acceptable to you. If tested levels are above that figure, you should have the right to back out of the contract without penalties. (Many standard forms contain a radon contingency addendum that can be added to your offer to purchase.) Ask your agent if radon testing is common in your area.

      Testing for Radon

      • Perform a radon test before you close on the property. Use EPA testing guidelines to choose a test and tester.
      • Ask the tester how you can prevent device interference during the test.
      • If radon levels are above 4 pCi/L, or your own stated maximum, use mitigation techniques for reduction, then test again.

      If Radon Levels Are Too High

      You can ask the seller to pay for the reduction system, but seller participation is usually not a requirement (unless your contract states it is).

      Radon Tips for Home Sellers

      Test your home for radon before you put it on the market. Use a long-term test if you have the time. If not, perform at least two short-term tests.

      You can do the initial test yourself to save money, home buyers are more impressed with test results from a qualified professional. To find out if your state requires specific licensing for radon professionals, refer to the EPA's list of contacts by region.

      If radon levels are too high, install a radon reduction system. Use the EPA's guidelines to help you choose a qualified radon service professional. Keep all installation details to share with your buyer.

      • Some systems can be installed in stages. The first stage might lower radon to an acceptable level. If not, the installer moves forward with the remaining steps.
      • Once radon levels are known, you will probably have to disclose them to potential buyers.
      • Even if you've tested the home, the buyer may perform a new test to verify the results.​
      • If you're building a home, install a radon reduction system now. It will be much less expensive than adding it later, and will probably be a more effective system.
      • Radon testing might be mandatory in some areas.

      Low radon levels are a selling point. If you find out now that there's a high amount of radon in your home, you'll have time to decide if you'll participate in a reduction system.

      EPA's Radon Video

      The EPA offers consumers a video about radon in real estate. Order a free copy by calling the Indoor Air Quality information line, 1-800-438-4318, and asking for publication number (EPA 402-V-02-003) (TRT 13.10). The more you know about radon, the better you will protect you and your family's health.

      Edited by Elizabeth Weintraub. At the time of writing, Elizabeth Weintraub, CalBRE #00697006, is a Broker-Associate at Lyon Real Estate in Sacramento, California.