Radon FAQs

A Guide to Radon, A Cancer Causing Radioactive Gas
What You May Not Know About Radon Can Kill You!

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The Environmental Protection Administration recommends

If you are planning on buying a home or selling your home, have it tested for radon.
For new homes, ask if radon resistant construction features have been used.
Fix the home if the radon level is 4 picocuries per liter (pCi/L) or higher.
Radon levels less than 4 pCi/L still pose a risk, and in many cases may be reduced.
Take steps to prevent device interference when conducting a radon test.

Radon is estimated to cause 5,000 to 20,000 lung cancer deaths per year in the U.S. This article is designed to help you understand a little more about radon.

Radon is a colorless, odorless, radioactive gas. Radon is produced when trace amounts of uranium and radium in the soil or rocks decay. The radon gas will then also decay into radioactive solid particles, called radon daughters or radon progenitors. Some of the short lived radon daughters attach themselves to small particles in the air, which can be inhaled deep into the lungs. The radon daughters may then damage dividing lung cells, possibly resulting in lung cancer.

The major sources of radon are:

Soil that contains radon releasing material
Water and natural gas that has passed through underground areas containing radon
Solar-heating systems that use radon-emitting rocks to store heat; granite rock and
Uranium or phosphate mine tailings.

Out-of-doors, radon poses little threat to our health because it is in such a low concentration. Indoors, however, radon can become more concentrated because of the lack of ventilation in homes combined with exhaust fans that draw air. Radon gas can seep into a house through dirt floors, cracks in concrete floors and walls, floor drains, sump pumps, and joints. Radon gas can also accumulate in private wells and be released into the home when water is used. This is normally not a problem for large community water supplies. The level of radon that can build up indoors depends upon the amount of radon in the source material and the rate at which it is removed from the home by ventilation. Homes tested throughout the US show a wide range of radon concentrations.

These quick, inexpensive steps advised by the EPA can be taken to help lower your risks from radon exposure: Stop smoking and discourage smoking in your home; it may increase the risk of radon exposure. Spend less time in areas with higher concentrations of radon, such as the basement. Whenever practical, increase the airflow into and through your house, especially in the basement. If you home has a crawl space beneath, keep the vents on all sides of the house fully open all year.

There are two commercially-available radon detectors, the charcoal canister and the alpha-track detector. Both of these are exposed to the air in your home for a specific time period and sent to a laboratory for analysis.

You Cannot See, Smell or Taste Radon. But it may be a problem in your home. That is because when you breathe air containing radon, you increase your risk of getting lung cancer. In fact, the Surgeon General has warned that radon is the second leading cause of lung cancer in the United States today. If you smoke and your home has high ration levels, your risk of lung cancer is especially high. You should test for radon Testing is the only way to find out your home's radon levels. EPA and the Surgeon General recommend testing all homes below the third floor for radon. You can fix a radon problem If you find that you have high radon levels, there are ways to fix a radon problem. Even very high levels can be reduced to acceptable levels.

If you are selling a home the EPA recommends that you test your home before putting it on the market and, if necessary, lower your radon levels. Save the test results and all information you have about steps that were taken to fix any problems. This could be a positive selling point. If you are buying a home the EPA recommends that you obtain the indoor radon level in a home you are considering buying. Ask the seller for radon test results. If the home has a radon reduction system, ask the seller for information about the system. If the home has not yet been tested, read our recommendations about how to test now. If you are buying a newly constructed home, please refer to that section.

The radon testing guidelines here have been developed specifically to deal with the time sensitive nature of home purchases and sales and the potential for radon device interference. The guidelines in this article are somewhat different from the guidelines in EPA publications which provide radon testing and reduction information for non-real estate situations. We discuss short term testing options when long term testing is not possible. We also recommend testing a home in the lowest level of the home which is currently suitable for occupancy. This is because a buyer may choose to live in a lower area of the home than that used by the seller.

Radon Has Been Found In Homes All Over the U.S.

Radon is a radioactive gas that has been found in homes all over the U.S. It comes from the natural breakdown of uranium in soil, rock and water and gets into the air you breathe. Radon typically moves up through the ground to the air above and into your home through cracks and other holes in the foundation. Your home can trap radon inside. Sometimes radon enters the home through well water.

Any home can have a radon problem. This means new and old homes, well sealed and drafty homes, and homes with or without basements. In fact, you and your family are most likely to get your greatest radiation exposure at home. That is where you spend most of your time.

Nearly 1 out of every 15 homes in the U.S. is estimated to have elevated radon levels. Elevated levels of radon gas have been found in homes in your state. Contact your state radon office for information about radon in your area. Testing is the only way to know if you and your family are at risk from radon. EPA and the Surgeon General recommend testing all homes below the third floor for radon.

You Cannot Estimate Radon Levels Based on State or Local Radon Measurements

Do not rely on radon test results taken in other homes in the neighborhood to estimate the radon level in your home. Homes which are next to each other have different indoor radon levels. Radon problems may be more common in some areas in the local community or state, however, any home may have a problem. Testing your home is the only way to find out what your radon levels are.

Selling A Home

If you are thinking of selling your home and you have already tested your home for radon, provide your test results to the buyer. Review the testing list to make sure that the test was done correctly. No matter what kind of test you took, a potential buyer may ask for a new test especially if: you took a test and checklist items were not met; you have renovated or altered your home since you tested; the buyer plans to live in a lower level of the house than you do, such as a basement which is suitable for occupancy but is not currently lived in; or your state requires disclosure of radon information to buyers.

If the home has not yet been tested for radon. Have a test taken as soon as possible. If you can, test your home before putting it on the market because this may save time during real estate transactions. You should test in the lowest level of the home which is suitable for occupancy and finished. This means testing in the lowest level that you currently live in or a lower level not currently used, but which a buyer could use for living space without renovations. The result of the radon test is important information about your home's radon level that potential buyers may want to. You can test your own home or hire an EPA listed or state certified radon tester. If you test your own home, carefully follow the EPA Checklist.

Buying A Home

If the home has been tested for ration. If you are thinking of buying a home, you may either decide to accept the test results from the seller, ask the seller to do another test, or you may ask for a new test to be conducted by an EPA listed or state certified radon tester.

If you decide to accept the seller's test, make sure that the seller (or whoever took the test) followed the EPA Test Checklist and that he or she can confirm that all the items were followed. If you plan to use the seller's test, find out as soon as possible from the seller: The results of the previous test; and who conducted the previous test: the homeowner, a radon professional, or some other person; and where in the home the previous test was taken, especially if you may plan to live in a lower level of the home. For example, the test may have been taken on the first floor; however, you may want to live in a basement which is not currently lived in, but which is suitable for occupancy without renovation. What, if any, structural changes or alterations have been made to the house since the test was done. Such changes might affect radon levels. If you decide that a new test is needed, you should discuss it with the seller as soon as possible. If you decide to use an EPA qualified or state certified radon tester, contact your state radon office for a list of radon testing companies.

If the home has not been tested for radon: Make sure that a radon test is done as soon as possible. You should consider including provisions in the contract specifying who should conduct the test, what type of test to do, when to do the test, and how the seller and the buyer will share the test results, test costs and, if necessary, when radon reduction measures should be taken and who should pay for them. Make sure that the test is done in the lowest level of the home suitable for occupancy. This means the lowest level that you are going to use as living space which is finished or does not require renovations prior to use. A state or local radon official or an EPA listed or state certified radon tester can help you make some of these decisions. If you decide to finish or renovate an unfinished area of the home in the future, ration tests should be taken before and after the area is finished. Radon reduction costs could be incurred if high levels are found in that area. Generally, it is less expensive to install a radon reduction system before or during renovations rather than afterwards.

Buying A Newly Built Home: What Should You Do?

New homes can be built with radon resistant features that minimize radon entry and allow easier fixing of radon problems that could occur later. These features cost less if installed during construction than if added to an existing home. In most new homes, use of radon resistant features will keep radon levels to below 2 pCi/L. Builders can incorporate radon resistant features into the homes they build. Some states, counties and local jurisdictions may adopt radon resistant construction features in their building codes, which builders must then follow. Radon resistant construction standards can be applied depending on the radon potential in a particular area. Many builders already use radon resistant building features.

New home buyers should ask if radon resistant construction techniques have been built into the new home they are considering for purchase. Buyers should also ask whether information about radon is available. For custom built homes, the buyer should discuss radon resistant features with the builder including the cost. Occupants of newly constructed should have their homes tested for radon. A long term test will provide a reading that more representative of the home's average radon level. However, short term tests may be used determine if elevated radon levels exist.

How Can You Get Reliable Radon Test Results?

Even though you cannot see or smell radon, it is not hard to find out if you have a radon problem in your home. Special equipment is needed to detect it. You can buy radon devices in retail stores when you want to test your own home, send away for radon devices from laboratories that offer mail order services, or you can hire an EPA listed or state certified radon tester who will test using radon devices that are appropriate for the situation.

There is a potential for test interference in real estate transactions. There are a number of ways to prevent or detect test interference such as:

Print out report which frequently records radon or decay product levels to detect unusual swings
Motion detectors to determine whether the test device has been moved or conditions have changed
Proximity detectors to reveal the presence of people in the room which may correlate to possible changes in radon levels during the test
Record of barometric pressure to identify weather conditions which may have affected the test
Temperature record to help assess whether doors and windows have been opened
Taping windows shut to ensure closed house conditions

Some of the most common radon testing devices are listed below. Because new testing devices may be listed by EPA or your state, you may want to check with your state radon office before you test to get the most up to date information.

Passive Devices

Passive radon testing devices do not need power to function. They include radon detectors such as charcoal canisters, alpha track detectors, and charcoal liquid scintillation devices that are available in hardware stores, drug stores, other stores, and by mail, and electret ion chamber detectors generally only available through laboratories. They are exposed to the air in the home for a specified period of time and then sent to a laboratory for analysis. Both short term and long term passive devices are generally inexpensive. Some of these devices may have features that offer more resistance to test interference or disturbance than other passive devices. Professional radon testers may use any of these devices to measure the home's radon level.

Active Devices

Active radon testing devices require power to function. Active radon detectors such as continuous ration monitors and continuous working level monitors require operation by trained testers. They work by continuously measuring and recording the amount of radon or its decay products in the air of the home. Many of these devices provide a report of this information which can reveal any unusual or abnormal swings in the radon level during the test period. A professional tester can explain this report to you. In addition, some of these devices are specifically designed to deter and detect test interference. Currently, some of the technically advanced active devices offer the most extensive device interference features. Although these tests may cost more, they may ensure a more reliable result.

General Information for All Devices

A state or local radon official can explain the differences between devices and recommend the ones which are most appropriate for your needs and expected testing conditions. In addition, EPA's Radon Measurement Protocols include technical information about the differences between devices. Make sure the radon device is listed by EPA's testing program or is state certified. The device may display the phrase "Meets EPA Requirements" or "EPA listed." Your state radon office or a radon tester can tell you more about radon testing devices.

Radon Test Device Placement

The testing device(s) should be placed in the lowest level of the home suitable for occupancy. This means testing in the lowest level currently lived in or a lower level not currently used, such as a basement, which a buyer could use for living space without renovations. The test should be in a room to be used regularly (like a living room, playroom, den or bedroom) but not a kitchen, bathroom or laundry room.

Whether you test for radon yourself, or hire an EPA or state certified tester, all radon tests should be taken for a minimum of 48 hours. A longer period of time is required for some devices.

The Two General Ways to Test for Radon

Long Term Testing

Long term tests remain in your home for more than 90 days. Alpha track, and electreion chamber detectors are commonly used for this type of testing. A long term test will give you a reading that is more likely to tell you your home's year round average radon level than a short term test. If time permits (more than 90 days) long term tests can be used to confirm initial short term results between 4 pCi/L and 10 pCi/L. When long term test results are 4 pCi/L or higher, EPA recommends fixing the home.

Short Term Testing

The quickest way to test is with short term tests. Short term tests remain in your home from two days to 90 days, depending on the device. There are two groups of devices which are more commonly used for short term testing. The passive device group includes alpha track detectors, charcoal canisters, charcoal liquid scintillation detectors, and electret ion chambers. The active device group consists of different types of continuous monitors. Because radon levels tend to vary from day to day and season to season, a short term test is less than a long term test to tell you your round average radon level. However, if need results quickly, short term testing be used to decide whether to fix the home.

If you are testing in a real estate transaction and you need results quickly, any of the following three ways to conduct Short Term Tests are acceptable for determining whether the home should be fixed. Any real estate test for radon should include steps to prevent or detect device interference.

There are trade offs among the short term test options. One test followed by another test (sequential) would most likely give a better representation of the seasonal average. Two tests taken at the same time (simultaneous) would improve the precision of the radon test. Both active and passive devices may have features which help to prevent test interference. Your state radon office can help you decide which option is the best for you.

Using Testing Devices Properly (If You Do the Test Yourself): When you are taking a short term test, close your windows and outside doors and keep them closed as much as possible during the test, except for normal entry and exit. If you are taking a short term test lasting less than 4 days, be sure to close your windows and outside doors at least 12 hours before beginning the test, too. You should not conduct short term tests lasting less than 4 days during severe storms or periods of high winds.

Place the test device at least 20 inches above the floor in a location where it will not be disturbed and where it will be away from drafts, high heat, high humidity, and exterior walls. Leave the test kit in place for as long as the test instructions say. Once you have finished the test, reseal the package and send it immediately to the lab specified on the package for analysis. You should receive your test results within a few weeks. If you need results quickly, you should find out how long results will take and, if necessary, request expedited service.

The EPA Testing Checklist

Follow this Checklist carefully so that you get the most accurate radon test results. Radon testing is not a complicated process, but must be done properly. Otherwise, the test results may not be accurate and more testing may have to be done. Disturbing or interfering with the test device or closed house conditions will invalidate the test results.

The seller, or an EPA listed or state certified tester, should be able to confirm that all the items in this Checklist have been followed. If the tester cannot confirm this, another test should be taken.

Before the Radon Test

Notify occupants of the importance of proper testing conditions. Give occupants written instructions or this document and explain the directions carefully.
If you conduct the test yourself, use a radon measurement device listed by EPA's Ration Measurement Proficiency (RMP) Program or certified by your state and follow the manufacturer's instructions that come with the device.
If you use a testing professional, only hire an EPA listed or state certified individual and ask to see his or her photo identification. The contractor's identification number should be clearly visible on the test report.
The test should include method(s) to prevent or detect interference with testing conditions or with the testing device itself.
Conduct the radon test for a minimum of 48 hours. Certain devices must be exposed for more than the 48 hour minimum.
Check to see if an active radon reduction system is in the house. Before taking a short term test lasting less than 4 days, make sure the fan, if any, is operating at least 24 hours before the beginning of the test.
EPA recommends that short term radon testing which lasts for no more than a week in length, be done under closed house conditions. Closed house conditions means keeping all windows closed, keeping doors closed except for normal entry and exit, and not operating fans or other machines which bring in air from outside. Note that fans that are part of a radon reduction system or small exhaust fans operating for only short periods of time may run during the test.
When doing short term testing lasting less than 4 days, it is important to maintain closed house conditions for at least 12 hours before the beginning of the test and for the entire test period. Do not operate fans or other machines which bring in air from the outside.

During the Radon Test

Maintain closed house conditions during the entire time of a short term test, especially for tests shorter than one week in length
Operate the home's heating and cooling systems normally during the test. For tests lasting less than one week, only operate air conditioning units which recirculate interior air
Do not disturb the test device at any time during the test
If a radon reduction system is in place, make sure the system is working properly and will be in operation during the entire radon test

After a Radon Test

If a high radon level is found, fix the home
Contact a qualified radon reduction contractor to lower the home's radon level
Be sure that you or the professional radon tester can demonstrate or provide information to ensure that the testing conditions were not violated during the testing period

If You Hire A Professional

In many cases, home buyers and sellers may decide to have the radon test done by a professional radon tester. Make sure that the company you hire is listed in EPA's Radon Measurement Proficiency (RMP) Program or your state's certification program, if it has one.

EPA's Radon Measurement Proficiency (RMP) program is designed to help you get reliable radon tests. RMP program participants are required to show their ability to make accurate tests and follow quality assurance and EPA test guidelines. EPA issues RMP reports for your state. These reports list testing companies and individuals in your area qualified to follow EPA's residential radon testing requirements. Make sure you ask to see the professional radon tester's photo I.D. card.

Interpreting Radon Test Results

The average indoor radon level is estimated to be about 1.3 pCi/L, and about 0.4 pCi/L of radon is normally found in the outside air. The U. S. Congress has set a long term goal that indoor radon levels be no more than outdoor levels. While this goal is not yet technologically achievable for all homes, the radon levels in some homes today can be reduced to 2 pCi/L or below.

What Will a Professional Radon Tester Do?

An EPA listed or state certified radon tester knows the proper conditions, test devices, and guidelines to get a reliable radon test. A professional radon tester can also:

Evaluate the home and recommend a testing approach designed to make sure you get reliable results
Explain how proper conditions can be maintained during the radon test
Emphasize to occupants of a home that a reliable test result depends on their cooperation because any interference or disturbance with the test or the closed house conditions, especially, during short term testing, will invalidate the test result
Analyze and report measurement results to you
Provide an independent test result by someone who is not involved in the home sale