Home Inspection | Guide To Radon In The Home

[A PDF version of this guidance is available here (PDF, 16 pgs., 1.17MB, About PDF)]

Contents Overview How Does Radon Get Into Your Home? How to Test Your Home There are Two General Ways to Test for Radon How to Use a Test Kit What Your Test Results Mean Radon and Home Sales Radon in Water How to Lower the Radon Levels in Your Home Radon and Home Renovations The Risk of Living With Radon Radon Risk Charts Radon Myths State Radon Contacts For Further Information How to Order Publications When you order a copy of this document, please ask for "A Citizen's Guide to Radon" EPA document number 402-K-02-006, Revised September 2005. Please Note:  The Spanish version of this publication, El Radon, reflects information that has NOT been updated  A translation of this version into Spanish has been planned.

EPA Recommends:

• Test your home for radon -- it's easy and inexpensive.
• Fix your home if your 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.

Radon is estimated to cause thousands of lung cancer deaths in the U.S. each year.
	* Radon is estimated to cause about 21,000 lung cancer deaths per year, according to EPA's 2003 Assessment of Risks from Radon in Homes (EPA 402-R-03-003).  The numbers of deaths from other causes are taken from the Centers for Disease Control and Prevention's 1999-2001 National Center for Injury Prevention and Control Report and 2002 National Safety Council Reports.

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Overview

Radon is a cancer-causing, radioactive gas.

You can't see radon. And you can't smell it or taste it. But it may be a problem in your home.

Radon is estimated to cause many thousands of deaths each year. That's because when you breathe air containing radon, you can get lung cancer. In fact, the Surgeon General has warned that radon is the second leading cause of lung cancer in the United States today. Only smoking causes more lung cancer deaths. If you smoke and your home has high radon levels, your risk of lung cancer is especially high.

Radon can be found all over the U.S.

Radon comes from the natural (radioactive) breakdown of uranium in soil, rock and water and gets into the air you breathe. Radon can be found all over the U.S. It can get into any type of building - homes, offices, and schools - and result in a high indoor radon level. But you and your family are most likely to get your greatest exposure at home, where you spend most of your time.

You should test for radon.

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. EPA also recommends testing in schools.

Testing is inexpensive and easy - it should only take a few minutes of your time. Millions of Americans have already tested their homes for radon (see How to Test Your Home).

You can fix a radon problem.

Radon reduction systems work and they are not too costly.  Some radon reduction systems can reduce radon levels in your home by up to 99%.  Even very high levels can be reduced to acceptable levels.

New homes can be built with radon-resistant features.

Radon-resistant construction techniques can be effective in preventing radon entry.  When installed properly and completely, these simple and inexpensive techniques can help reduce indoor radon levels in homes.  In addition, installing them at the time of construction makes it easier and less expensive to reduce radon levels further if these passive techniques don't reduce radon levels to below 4 pCi/L.  Every new home should be tested after occupancy, even if it was built radon-resistant.  If radon levels are still in excess of 4 pCi/L, the passive system should be activated by having a qualified mitigator install a vent fan.  For more explanation of radon resistant construction techniques, refer to EPA publication, Building Radon Out: A Step-by-Step Guide on How to Build Radon-Resistant Homes (see EPA Publications).

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How Does Radon Get Into Your Home?

Radon is a radioactive gas.  It comes from the natural decay of uranium that is found in nearly all soils. It typically moves up through the ground to the air above and into your home through cracks and other holes in the foundation. Your home traps radon inside, where it can build up. Any home may have a radon problem. This means new and old homes, well-sealed and drafty homes, and homes with or without basements.

Radon from soil gas is the main cause of radon problems. Sometimes radon enters the home through well water (see "Radon in Water" below). In a small number of homes, the building materials can give off radon, too. However, building materials rarely cause radon problems by themselves.

RADON GETS IN THROUGH: Cracks in solid floors Construction joints Cracks in walls Gaps in suspended floors Gaps around service pipes Cavities inside walls The water supply

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 general information about radon in your area. While radon problems may be more common in some areas, any home may have a problem. The only way to know about your home is to test.

Radon can also be a problem in schools and workplaces.  Ask your state radon office about radon problems in schools, daycare and childcare facilities, and workplaces in your area.

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How to Test Your Home

You can't see radon, but it's not hard to find out if you have a radon problem in your home. All you need to do is test for radon. Testing is easy and should only take a few minutes of your time.

The amount of radon in the air is measured in "picoCuries per liter of air," or "pCi/L." Sometimes test results are expressed in Working Levels (WL) rather than picoCuries per liter (pCi/L) (4 pCi/L equals to 0.016 WL). There are many kinds of low-cost "do-it-yourself" radon test kits you can get through the mail and in hardware stores and other retail outlets.  If you prefer, or if you are buying or selling a home, you can hire a qualified tester to do the testing for you.  You should first contact your state radon office about obtaining a list of qualified testers.  You can also contact a private radon proficiency program for lists of privately certified radon professionals serving your area.  For links and information, visit www.epa.gov/radon/proficiency.html .

There are Two General Ways to Test for Radon:

SHORT-TERM TESTING:

The quickest way to test is with short-term tests. Short-term tests remain in your home for two days to 90 days, depending on the device. "Charcoal canisters," "alpha track," "electret ion chamber," "continuous monitors," and "charcoal liquid scintillation" detectors are most commonly used for short-term testing. 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. If you need results quickly, however, a short-term test followed by a second short-term test may be used to decide whether to fix your home (see Home Sales).

LONG-TERM TESTING:

Long-term tests remain in your home for more than 90 days. "Alpha track" and "electret" 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.

How To Use a Test Kit:

Follow the instructions that come with your test kit. If you are doing a short-term test, close your windows and outside doors and keep them closed as much as possible during the test. Heating and air-conditioning system fans that re-circulate air may be operated.  Do not operate fans or other machines which bring in air from outside.  Fans that are part of a radon-reduction system or small exhaust fans operating only for short periods of time may run during the test.  If you are doing a short-term test lasting just 2 or 3 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 just 2 or 3 days during unusually severe storms or periods of unusually high winds.  The test kit should be placed in the lowest lived-in level of the home (for example, the basement if it is frequently used, otherwise the first floor). It should be put in a room that is used regularly (like a living room, playroom, den or bedroom) but not your kitchen or bathroom. Place the kit at least 20 inches above the floor in a location where it won't be disturbed - away from drafts, high heat, high humidity, and exterior walls. Leave the kit in place for as long as the package says. Once you've finished the test, reseal the package and send it to the lab specified on the package right away for analysis. You should receive your test results within a few weeks.

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What Your Test Results Mean

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 in all cases, most homes today can be reduced to 2 pCi/L or below.

Sometimes short-term tests are less definitive about whether or not your home is above 4 pCi/L. This can happen when your results are close to 4 pCi/L. For example, if the average of your two short-term test results is 4.1 pCi/L, there is about a 50% chance that your year-round average is somewhat below 4 pCi/L. However, EPA believes that any radon exposure carries some risk - no level of radon is safe. Even radon levels below 4 pCi/L pose some risk, and you can reduce your risk of lung cancer by lowering your radon level.

If your living patterns change and you begin occupying a lower level of your home (such as a basement) you should retest your home on that level.

Even if your test result is below 4 pCi/L, you may want to test again sometime in the future.

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Radon in Water

There are two main sources for the radon in your home's indoor air, the soil and the water supply. Compared to radon entering the home through water, radon entering your home through the soil is usually a much larger risk.

The radon in your water supply poses an inhalation risk and an ingestion risk.  Research has shown that your risk of lung cancer from breathing radon in air is much larger than your risk of stomach cancer from swallowing water with radon in it.  Most of your risk from radon in water comes from radon released into the air when water is used for showering and other household purposes.

Radon in your home's water is not usually a problem when its source is surface water.  A radon in water problem is more likely when its source is ground water, e.g. a private well or a public water supply system that uses ground water. If you are concerned that radon may be entering your home through the water and your water comes from a public water supply, contact your water supplier.

If you've tested your private well and have a radon in water problem, it can be fixed.  Your home's water supply can be treated in two ways.  Point-of-entry treatment can effectively remove radon from the water before it enters your home.  Point-of-use treatment devices remove radon from your water at the tap, but only treat a small portion of the water you use and are not effective in reducing the risk from breathing radon released into the air from all water used in the home.

For more information, call EPA's Drinking Water Hotline at (800) 426-4791 or visit www.epa.gov/safewater/radon.html  If your water comes from a private well, you can also contact your state radon office.

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How to Lower the Radon Level in Your Home

Since there is no known safe level of radon, there can always be some risk. But the risk can be reduced by lowering the radon level in your home.

There are several proven methods to reduce radon in your home, but the one primarily used is a vent pipe system and fan, which pulls radon from beneath the house and vents it to the outside.  This system, known as a soil suction radon reduction system, does not require major changes to your home.  Sealing foundation cracks and other openings makes this kind of system more effective and cost-efficient.  Similar systems can also be installed in houses with crawl spaces. Radon contractors can use other methods that may also work in your home. The right system depends on the design of your home and other factors.

Ways to reduce radon in your home are discussed in EPA's "Consumer's Guide to Radon Reduction." You can get a copy from your state radon office.

The cost of reducing radon in your home depends on how your home was built and the extent of the radon problem. Most homes can be fixed for about the same cost as other common home repairs. The average house costs about $1,200 for a contractor to fix, although this can range from about $800 to about $2,500.  The cost is much less if a passive system was installed during construction.

Note:  This diagram is a composite view of several mitigation options.  The typical mitigation system usually has only one pipe penetration through the basement floor; the pipe may also be installed on the outside of the house.

Lowering high radon levels requires technical knowledge and special skills. You should use a contractor who is trained to fix radon problems.  A qualified contractor can study the radon problem in your home and help you pick the right treatment method. Check with your state radon office for names of qualified or state certified radon contractors in your area.  You can also contact private radon proficiency programs for lists of privately certified radon professionals in your area.  For more information on private radon proficiency programs, visit www.epa.gov/radon/proficiency.html  Picking someone to fix your radon problem is much like choosing a contractor for other home repairs - you may want to get references and more than one estimate. If you are considering fixing your home's radon problem yourself, you should first contact your state radon office for guidance and assistance. You should also test your home again after it is fixed to be sure that radon levels have been reduced. Most soil suction radon reduction systems include a monitor that will indicate whether the system is operating properly.  In addition, it's a good idea to retest your home every two years to be sure radon levels remain low.

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The Risk of Living With Radon

Radon gas decays into radioactive particles that can get trapped in your lungs when you breathe. As they break down further, these particles release small bursts of energy. This can damage lung tissue and lead to lung cancer over the course of your lifetime. Not everyone exposed to elevated levels of radon will develop lung cancer. And the amount of time between exposure and the onset of the disease may be many years.

Like other environmental pollutants, there is some uncertainty about the magnitude of radon health risks. However, we know more about radon risks than risks from most other cancer-causing substances. This is because estimates of radon risks are based on studies of cancer in humans (underground miners).

Smoking combined with radon is an especially serious health risk. Stop smoking and lower your radon level to reduce your lung cancer risk.

Children have been reported to have greater risk than adults of certain types of cancer from radiation, but there are currently no conclusive data on whether children are at greater risk than adults from radon.

Your chances of getting lung cancer from radon depend mostly on:

• How much radon is in your home
• The amount of time you spend in your home
• Whether you are a smoker or have ever smoked

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Radon Risk If You Smoke

Radon Risk If You've Never Smoked

It's never too late to reduce your risk of lung cancer.  Don't wait to test and fix a radon problem.  If you are a smoker, stop smoking.

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Radon Myths

MYTH: Scientists are not sure that radon really is a problem.

FACT: Although some scientists dispute the precise number of deaths due to radon, all the major health organizations (like the Centers for Disease Control and Prevention, the American Lung Association and the American Medical Association) agree with estimates that radon causes thousands of preventable lung cancer deaths every year. This is especially true among smokers, since the risk to smokers is much greater than to non-smokers.

MYTH: Radon testing is difficult, time-consuming and expensive.

FACT: Radon testing is easy.  You can test your home yourself or hire a qualified radon test company.  Either approach takes only a small amount of time and effort.

MYTH: Radon testing devices are not reliable and are difficult to find.

FACT: Reliable testing devices are available from qualified radon testers and companies.  Reliable testing devices are also available by phone or mail-order, and can be purchased in hardware stores and other retail outlets.  Call your state radon office for help in identifying radon testing companies.

MYTH: Homes with radon problems can't be fixed.

FACT: There are simple solutions to radon problems in homes. Hundreds of thousands of homeowners have already fixed radon problems in their homes. Radon levels can be readily lowered for $800 to $2,500 (with an average cost of $1,200).. Call your state radon office for help in identifying qualified mitigation contractors.

MYTH: Radon affects only certain kinds of homes.

FACT: House construction can affect radon levels.  However, radon can be a problem in homes of all types:  old homes, new homes, drafty homes, insulated homes, homes with basements, and homes without basements.  Local geology, construction materials, and how the home was built are among the factors that can affect radon levels in homes.

MYTH: Radon is only a problem in certain parts of the country.

FACT: High radon levels have been found in every state. Radon problems do vary from area to area, but the only way to know your radon level is to test.

MYTH: A neighbor's test result is a good indication of whether your home has a problem.

FACT: It's not. Radon levels can vary greatly from home to home. The only way to know if your home has a radon problem is to test it.

MYTH: Everyone should test their water for radon.

FACT:  Although radon gets into some homes through water, it is important to first test the air in the home for radon. If your water comes from a public water supply that uses ground water, call your water supplier.  If high radon levels are found and the home has a private well, call the Safe Drinking Water Hotline at 1 800-426-4791 for information on testing your water.

MYTH: It's difficult to sell homes where radon problems have been discovered.

FACT: Where radon problems have been fixed, home sales have not been blocked or frustrated. The added protection is some times a good selling point.

MYTH: I've lived in my home for so long, it doesn't make sense to take action now.

FACT: You will reduce your risk of lung cancer when you reduce radon levels, even if you've lived with a radon problem for a long time.

MYTH: Short-term tests can't be used for making a decision about whether to fix your home.

FACT: A short-term test, followed by a second short-term test* can be used to decide whether to fix your home. However, the closer the average of your two short-term tests is to 4 pCi/L, the less certain you can be about whether your year-round average is above or below that level. Keep in mind that radon levels below 4 pCi/L still pose some risk.  Radon levels can be reduced in most homes to 2 pCi/L or below.

*  If the radon test is part of a real estate transaction, the result of two short-term tests can be used in deciding whether to mitigate.  For more information, see EPA's "Home Buyer's and Seller's Guide to Radon".

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For Further Information

www.epa.gov/radon  EPA's main radon page.  Includes links to publications, hotlines, private radon proficiency programs and more.

• Home Buyer's and Seller's Guide to Radon  [En Espaol]
• Consumer's Guide to Radon Reduction
• Radon Guide for Tenants
• Application of Radon Reduction Techniques for Detached Homes
• EPA Map of Radon Zones and Fact Sheet
• Buying a New Home?  How to Protect Your Family From Radon
• Building a New Home, Have You Considered Radon?
• Building Radon Out: A Step-by-Step Guide on How to Build Radon-Resistant Homes
• EPA Assessment of Risks from Radon in Homes
• Technical Support Document to the 1992 Citizens Guide to Radon
   
• Other Radon-specific publications are located at: www.epa.gov/radon/pubs/
• Other Indoor Air Quality-specific publications are located at: www.epa.gov/iaq/pubs/

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State and Regional Radon and Indoor Air Quality Contacts

Call your state radon office for additional help with any of your radon questions.  Up-to-date information on how to contact your state radon office is also available on EPA's web site at www.epa.gov/iaq/whereyoulive.html , or call EPA's toll free Indoor Air Quality Information Clearinghouse (IAQINFO) at (800) 438-4318 to obtain the current listing.

How to Order Publications from EPA

IAQ INFO
P.O. Box 37133, Washington, DC 20013-7133
1-800-438-4318/703-356-4020
(fax) 703-356-5386
iaqinfo@aol.com

or, you can order this publication directly via EPA's National Service Center for Environmental Publications (NSCEP) (http://www.epa.gov/ncepihom/). web site. Your publication requests can also be mailed, called or faxed directly to:

U.S. Environmental Protection Agency
National Center for Environmental Publications (NSCEP)
P.O. Box 42419
Cincinnati, OH 42419
1-800-490-9198/(513) 489-8695 (fax)

This document was prepared by the U.S. EPA, Indoor Environments Division (6609J), Washington, D.C. 20460 | U.S. EPA 402-K-02-006, Revised September 2005

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