What is Radon?
How does Radon get into my house?
What are the health effects associated with Radon?
My neighbor doesn’t have high Radon. Do I need to test?
How do I test for Radon?
What level is considered "safe"?
Can the problem be fixed and for how much?
Where can I get more information?
Tell me about testing for Radon during a non-realestate transfer?
Tell me about testing for a realestate transfer?
What are the testing options for real estate transactions?
What are Passive Radon Devices?
What are Active Radon Devices?
What are short-term and long-term tests?
What are Long Term Tests?
How do I reduce radon levels in my home?
My results are high, how soon should I fix my home?
What is the link between radon and lung cancer?
What about radon in water?
RADON FACT SHEET

What is Radon?

Radon is a colorless, odorless, tasteless and chemically inert gas. It is a byproduct of naturally occurring decay of uranium in rock, soil and water. It can be found in all 50 states. Radon moves through the ground to the air above. Some remains below the surface and dissolves in water that collects and flows under the ground’s surface.


Radon itself is less dangerous to our health than the products it decays into. These products (progeny) are charged particles that can easily attach to dust. These charged dust particles are easily inhaled. The radioactive particles have a very short half life, decaying in the lungs and releasing small amounts of radioactivity when doing so. Lung tissue is damaged and may lead to cancer over time.


Often testing measures for the presence of radon and not the progeny. When progeny are measured, the data is usually expressed in Working Level (WL) Units. When radiation from radon is measured directly (most common, the data is usually expressed in Picocuries per liter of air (pCi/L).

Remember that Radon is a radioactive gas. Trapped gasses build up pressure. As air leaves the attic of a home, a negative pressure field is formed, drawing soil gasses through floors and walls.


Very high Radon in water can add to levels in the home. Typically, Radon levels in water must be extremely high to make a significant contribution to the overall Radon gas level in a home. This is normally not seen in this area of Wisconsin.

The Surgeon General has warned that Radon is the second leading cause of lung cancer in the US. Only smoking causes more cases of lung cancer. Smokers exposed to elevated Radon levels have a much higher risk of lung cancer.


Radon exposure does not cause any short-term health effects such as shortness of breath, headaches, respiratory illnesses, coughing or headaches.


Water with high levels of radon may also pose a risk. However, the risks associated with water are much lower than that of radon in air.

Yes, Radon levels can vary from area to area, home to home a near as a few feet.

You can test for radon with an EPA-listed kit or by hiring an EPA-listed contractor to test you home for you. You can contact the Radon information center for a kit at 1-888-LOW RADON. If available, kits are free to persons within the county consortium. The kits distributed by the consortium are simple, easy to use, and come with full instructions. Test kits will allow homeowners to get a picture as to what their short term levels of radon in air are.

The EPA states that any radon exposure may carry some risk, however; they recommend that homes be fixed if an occupant’s long term exposure will average 4 picocuries per liter (pCi/L) or higher. Four Picocuries relates to approximately 12,500 radioactive disintegrations per minute in a liter of air during a 24 hour period.

Yes, the radon problem can be fixed with a mitigation system installed that meets the needs of each individual home. Typically, a sub-slab depressurization system needs to be installed. This is the most common and most effective system in our area. Costs differ based on the home but can run anywhere from $600 to $1200. Although we recommend that you use a proficiency competent. Many times homeowners can install the systems themselves.


Radon resistant construction can be incorporated when building. Costs typically will be under $100 for the materials. Contact the information center for more information.

The National Environmental Health Association (NEHA) National Radon Proficiency Program at 1-800-269-4174. Website: http://www.radongas.org and the State radon program at http://www.dhfs.state.wi.us/dph_beh/RadonProt/

You can test your own home with kits available from the Health Department or a hardware store. Your first radon measurement should be a short term test ( two day minimum ) in the lowest LIVED IN level of your home, with the windows kept closed. Note: It is important to have closed living conditions at least 12 hours prior to the start of the test as well.


A basement can be considered lived in if it is occupied at least 7 hours per week. Otherwise, the main floor is the best place to test or do a follow up test. The testing for real estate transfers is some what different.


Your test results will be reported in units of pCi/L (picoCuries of radon per liter of air), a measure or radon concentration. Appropriate follow up actions based on the results of your first measurement are:



First result <4 pCi/L:


No immediate follow up needed. Your home has fairly safe radon levels. Testing should again be performed should any changes be made to your home or to the land around your home.




First result between 4-10 pCi/L:


Do a year long follow up measurement with an alpha-track detector to determine your average radon exposure. Radon levels may change with seasons, and can be low when closed conditions are not kept. The average radon level in occupied floors of your home determines your lung cancer risk.




First result above 10 pCi/L:


Do a second short term test to confirm the accuracy of your first test. If second test is also above 4, it is highly recommended that you hire a contractor certified in radon mitigation to fix the problem.




If follow up measurements indicate your radon exposure is higher than 4 pCi/L, it can be significantly reduced. The higher your confirmed radon results are, the more important it is to fix your home. Outdoor air has about 0.5 pCi/L, and is the lowest achievable level in a house. The average radon level in the lowest lived in floors of homes in Wisconsin is about 1.8 pCi/L . Twenty five per cent of the homes in the state have radon levels over 4 pCi/L in basements. In some regions of the state, more than half the homes are over 4 pCi/L in the basement. But, not all of those basements are significantly occupied. It is important to have the radon level tested in spaces that are occupied for several hours a day.

The major testing difference for real estate transfers is the way the tests are performed and at what level of the home the tests are performed at. The radon test device placement for real estate transactions should be at the lowest level of the home suitable for occupancy in which a buyer could use for living space without renovations and not a bathroom, kitchen, or laundry room.


If you are thinking of selling your home and you have already tested your home for radon, the buyer may ask for a new test if your altered your home since you’ve tested, the buyer plans to live in a lower level of the house than you do, or for disclosure reasons on a transaction.


If you are purchasing a new home and require a radon test to be done prior to the sale, you should request that the test be performed by a certified radon measurement contractor. The test should have either a:


1.) Print-out report which frequently records radon or decay product levels to detect unusual swings.


2.) Motion detectors to determine whether the test device has been moved or testing conditions have changed.


3.) Proximity detectors to reveal the presence of people in the room which may correlate to possible changes in radon levels during the test.


4.) Record of barometric pressure to identify weather conditions which may have affected the test or the tampering of a test by not maintaining closed conditions.


5.) Temperature record to help assess whether doors and windows have been opened; and taping windows shut to ensure closed house conditions.

Short-Term Radon Testing Options


Passive Tests Initial and Follow:


Take an initial short- term test for at least 48 hours. After the first test has been completed, take a follow-up short-term test for at least another 48 hours.



Passive Tests Side by Side:


Take two short-term tests at the same time in the same location for at least 48 hours.



Active Tests:


Test the home with a continuous monitor for at least 48 hours.



What You Would Do According To The Results


Passive Test Initial and Follow:


Average the results of the two separate tests by adding the results and dividing that number by 2. If the average of the two tests come to more than 4 pCi/L, fix the home.




Passive Test Side by Side:


Average the results of the two separate tests by adding the results and dividing that number by 2. If the average of the two tests come to more than 4 pCi/L, fix the home.




Active Tests:


Fix the home if the average of the continuous monitor test results are above 4 pCi/L.

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. Electret ion chamber detectors generally are 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 radon testing devices require power to function. Active radon detectors such as Continuous radon 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 features. Although these tests may cost more, they may ensue a more reliable result.

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 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 likely than a long-term test to tell you your year-round average radon level. However, if you need results quickly, short-term testing may be used to decide whether to fix the home.

The long-term tests remain in your home more than 90 days. Alpha track and electret ion 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 test results between 4pCi/L and 10 pCi/L. When long-term test results are 4 pCi/L or higher, EPA recommends fixing the home.

For radon reduction work, you should always consider the use of contractors who are certified in a radon proficiency program. To get a copy of the Radon Mitigation Contractor Proficiency List for the state, call one of the Wisconsin Radon Information Centers toll free at 888-569-7236 ( 888 LOW-RADON ), or access the National Environmental Health Association’s Radon Proficiency web page. http://search.freefind.com/find.html?id=8311268&pid=r&mode=ALL&query=Radon&t=s


Sealing Cracks:


Virtually all radon in Wisconsin comes from the soil beneath houses. Radon at 300 to 1,000 pCi/L or more is in the gasses in the soil under basement floors everywhere. The caulk type with the best adhesion to concrete is polyurethane. However, experience by research has shown that sealing cracks and openings in the basements will result in reductions of radon by more than 50% in only about 20% of the houses in which it is applied. Since it can be inexpensive and is part of the next method, it may be worth a try, but one shouldn’t expect it will necessarily have a major effect. It might reduce radon levels significantly if the area of openings that are sealed adds up to several square inches. Hairline cracks are not worth sealing.



Soil Depressurization:


This is usually highly effective, reducing radon to below 2 pCi/L. Air is withdrawn from a sump placed beneath the basement floor. This reduces the air pressure below the floor so air in the basement flows down to the depressurized zone through small cracks and openings that could not be sealed, instead of soil gases containing radon flowing up into the basement through those openings. The cost for a proficiency listed contractor to install a system is usually around $1,200 and can range from $800 to $2000 depending on the site. Sub-Slab depressurization is not a do-it-yourself project unless you have considerable contractor skills. All public libraries in Wisconsin have copies of an eleven-minute videotape, Radon Reduction: Sub-Slab Depressurization, showing a system installed and how it works.


For more information on reducing radon, consult the Health Department, the Radon Information Centers and proficiency listed radon mitigation contractors. It you have Internet access, you can also look on the U.S. EPA radon web page.

If the results in occupied levels of your home are confirmed to be in the range of 4 to 20 pCi/L, you can reasonably take a year to get the work done. For confirmed results above 20 pCi/L, mitigation action should probably be more prompt. Consult one of the Wisconsin Radon Information Centers, toll free at 888 569-7236.

Radon is the second leading cause of lung cancer, after smoking. That’s why the United States Environmental Protection Agency and the Surgeon General strongly recommend that all homes be tested and , if a problem exists, corrective action be taken.


Your lung cancer risk from radon is determined by the amount in the air you breathe and the length of time you breathe it. The higher the level, the greater the risk. The U.S. EPA has estimated that the chance for an individual of lung cancer caused by breathing 4 pCi/L in a house for many decades is about 0.2% for people who never smoke, 3% for current smokers, and between these percentages for former smokers. The comprehensive report, Health Effects of Exposure to Radon, BEIR VI, issued by the National Academy of Sciences in February, 1998, indicates a somewhat higher individual lung cancer risk, about 0.5% for never smokers at 4pCi/L for a whole lifetime, about 74 years. For one year of exposure, your risk would be about 1/70 times these estimates. Note that because main floor radon levels are typically about half of basement radon levels, one should not use basement radon measurements to estimate the risk from radon unless the basement is occupied for a significant portion of the time.


For further information about radon and lung cancer, see the EPA radon web page.

EPA has proposed a drinking water standard for public well supplies for the state. The proposal requires municipalities to meet the required standard or do public education in conjunction with reducing radon levels. I am not aware of any municipal supplies within the three counties that exceeded this standard.

Radon Fact Sheet.