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Radon FAQ’s

On this page you will find radon questions with short and concise answers. There are links to other pages and posts on this site which give more detailed answers.

Frequently Asked Radon Questions Radon3 300x274 Radon FAQs

What is radon?

Where Does Radon Come From?

What health effects are associated with radon exposure?

What is the “acceptable” level of radon in air?

What is a “picocurie” (pCi)?

What is a “working level” (WL)?

How often is indoor radon a problem?

How does radon get into a building?

Can the radon level in a building’s air be predicted?

Where can I get more information about radon issues?

Questions About Testing For Radon

Why should I test my home for radon?

Who can test a building for radon?

What testing protocol should be followed?

Why are short- and long-term tests used?

What kinds of test devices are used?

Where should home testing be done?

If a test result is less than 4 pCi/L (0.02 WL), what should be done next?

If an initial short-term test result is 4 pCi/L (0.02 WL) or higher, what should be done next?

Questions About Radon Resistant Construction

What does radon resistant construction incorporate?

When should radon-resistant construction be considered?

What are the benefits of radon-resistant construction?

How much does it cost to reduce radon in an existing home?

Who should I hire to install radon-resistant features?

Should a home built with radon-resistant features be tested?

Questions About Reducing Radon or Radon Mitigation

(also called Radon Remediation, Radon Abatement and Radon Reduction)

Mitigating Radon Problems

What is a radon mitigation system?

What are the benefits of radon mitigation?

What can be done to reduce radon in a home?

How much does it cost to reduce radon in an existing home?

Who should I hire to correct a radon problem?

Will any more testing be needed after a radon mitigation system has been installed?

Are funds available to reduce high radon levels in rental housing?

Radon Questions About Water

Radon in Water

How does radon get in water?

Does radon in drinking water pose a risk?

Should drinking water be tested?

What do the results of a water test mean?

What levels of radon in water should I be concerned about?

How is radon removed from water?

General Radon Questions

What is radon?222 Rn 86 Radon1 Radon FAQs

Radon is a radioactive gas. It is colorless, odorless, tasteless, and chemically inert. Unless you test for it, there is no way of telling how much is present.

Radon is formed by the natural radioactive decay of uranium in rock, soil, and water. Naturally existing, low levels of uranium occur widely in Earth’s crust. It can be found in all 50 states. Once produced, 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 has a half-life of about four days—half of a given quantity of it breaks down every four days. When radon undergoes radioactive decay, it emits ionizing radiation in the form of alpha particles. It also produces short-lived decay products, often called progeny or daughters, some of which are also radioactive.

Unlike radon, the progeny are not gases and can easily attach to dust and other particles. Those particles can be transported by air and can also be breathed.  The decay of progeny continues until stable, non-radioactive progeny are formed. At each step in the decay process, radiation is released.

Sometimes, the term radon is used in a broad sense, referring to radon and its radioactive progeny all at once. When testing measures radiation from the progeny, rather than radon itself, the measurements are usually expressed in working level (WL) units. When radiation from radon is measured directly, the amount is usually expressed in picocuries per liter of air (pCi/L).  Back to top

What health effects are associated with radon exposure?

The Surgeon General has warned that radon is the second leading cause of lung cancer in the United States. There are currently no conclusive data on whether children are at greater risk than adults from radon. No specific subtype of lung cancer is associated with radon exposure.

Only smoking causes more cases of lung cancer. If you smoke and you are exposed to elevated radon levels, your risk of lung cancer is especially high. The U.S. Environmental Protection Agency provides radon risk comparison charts for people who smoke and those who have never smoked. Stop smoking and lower your radon level to reduce your lung cancer risk.

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.

Breathing radon does not cause any short-term health effects such as shortness of breath, coughing, headaches, or fever.

In 1998, the National Academy of Sciences (NAS) released the Biological Effects of Ionizing Radiation (BEIR VI) Report, “The Health Effects of Exposure to Indoor Radon.” The study reviewed and evaluated data from many prior studies and drew conclusions. It fully supports estimates by the EPA that radon causes about 21,000 lung cancer deaths per year. Though some people debate the number of deaths, it is widely agreed that radon exposure is the second leading cause of lung cancer.

Research suggests that swallowing water with high radon levels may pose risks, too, although risks from drinking water containing radon are much lower than those from breathing air containing radon. A NAS report on radon in drinking water, “Risk Assessment of Radon in Drinking Water,” was released in 1999. It concluded drinking radon in water causes about 19 stomach cancer deaths per year.

The EPA provides more information about health effects from radon in their publication, Radon—A Physician’s Guide.

What is the “acceptable” level of radon in air?

The EPA states that any radon exposure carries some risk; no level of radon exposure is always safe. However, the EPA recommends homes be fixed if an occupant’s long-term exposure will average 4 picocuries per liter (pCi/L) or higher. They also state that even if the radon level is below 4 pCi/L you may want to lower it if it is above 2 pCi/L, this would apply to a situation where someone is in the home most of the time, like young children and infants who are also more susceptible to the effects of radon.

What is a “picocurie” (pCi)?

A pCi is a measure of the rate of radioactive decay of radon. One pCi is one trillionth of a Curie, 0.037 disintegrations per second, or 2.22 disintegrations per minute. Therefore, at 4 pCi/L (picocuries per liter, the EPA’s recommended action level), there will be approximately 12,672 radioactive disintegrations in one liter of air during a 24-hour period.

What is a “working level” (WL)?

Some devices measure radiation from radon decay products, rather than radiation coming directly from radon. Measurements from these devices are often expressed as WL. As noted above, conversions from WL to pCi/L are usually approximate. A level of 0.02 WL is usually equal to about 4 pCi/L in a typical home.

If a working level (WL) value is converted to a radon level (pCi/L), the conversion is usually approximate and is based on a 50 percent equilibrium ratio. If the actual equilibrium ratio is determined (which is rare), it should be stated. The 50 percent ratio is typical of the home environment, but any indoor environment may have a different and varying relationship between radon and its decay products.  Technically speaking, 1 WL represents any combination of short-lived radon decay products in one liter of air that will result in the ultimate emission of 1.3 x 105 MeV of potential alpha energy.

How often is indoor radon a problem?

Nearly one out of every 15 homes has a radon level the EPA considers to be elevated—4 pCi/L or greater. The U.S. average radon-in-air level in single family homes is 1.3 pCi/L. Because most people spend as much as 90 percent of their time indoors, indoor exposure to radon is an important concern.

How does radon get into a building? radon home Radon FAQs

Most indoor radon comes into a building from the soil or rock beneath it. Radon and other gases are pushed up through the soil which is under positive pressure. The atmosphere is at a neutral pressure, most radon disperses into the air, becomes highly diluted in the atmosphere and poses no threat.

The indoor air of most buildings is at a negative pressure, some more some less. During cold weather you can feel the cold air being pulled into the house at cracks and window and door seals. Sometimes, in large building you can feel the air rushing out when you open a door.  This negative pressure inside a building literally pulls air in from outside including from the soil below.

Buildings literally suck the radon gas out of the soil. Most of the gas moves through cracks and other openings. Radon gas simply follows the path of least resistance. Once inside, the radon can become trapped and concentrated. This is more true for a well sealed and insulated home verses a older home not so well insulated, with drafty windows and doors.

Openings which commonly allow easy flow of the gases in include the following:

•          Cracks in floors and walls

•          Gaps in suspended floors

•          Openings around sump pumps and drains

•          Cavities in walls

•          Joints in construction materials

•          Gaps around utility penetrations (pipes and wires)

•          Crawl spaces that open directly into the building

Even if all of the above are well sealed, radon can still come right through solid concrete, the radon atoms can easily move through the larger molecules that make up concrete. Radon gas can not however easily pass through most plastic vapor barrier sheeting. Polyethylene sheet plastic in either 4- or 6-millimeter thickness is commonly used for vapor barrier under concrete slabs and crawl space floors, to stop radon gas it needs to be completely sealed at all seams and edges, the thicker the sheeting the better 10 mil or more is best.

Radon may also be dissolved in water, particularly well water. After coming from a faucet, about one ten thousandth of the radon in water is typically released into the air. The more radon there is in the water, the more it can contribute to the indoor radon level.

Trace amounts of uranium are sometimes incorporated into materials used in construction. These include, but are not limited to concrete, brick, granite, drywall and even wood to a lesser degree. Though these materials have the potential to produce radon, they are rarely the main cause of an elevated radon level in a building. Radon above 4 pCi/L has been found, many stories up, in high rise buildings, the source being, the floors and ceilings which are constructed of thick concrete.

Outdoor air that is drawn into a building can also contribute to the indoor radon level. The average outdoor air level for the United States is about 0.4 pCi/L, but it can be higher in some areas. I tested the outdoor air for radon in the yard of a home in Ithaca, New York, placing a professional digital radon monitor on a step stool about 3 feet off the ground, 10 feet from the house, the radon level was 10.5 pCi/L that’s about 2.5 times above the safety action level set by the EPA.

While radon problems may be more common in some geographic areas, any home may have an elevated radon level. New and old homes, well-sealed and drafty homes, and homes with or without basements can have a problem. Homes below the third floor of a multi-family building are particularly at risk. Also many schools, office, and commercial buildings have high radon, most of these have much higher negative indoor air pressure than a typical home.

Can the radon level in a building’s air be predicted?

No, it is not possible to make a reliable prediction.

The only way to determine the level is to test.  The EPA and the Surgeon General recommend testing all homes below the third floor for radon.

A map of radon zones has been created to help national, state, and local organizations to target their resources and to implement radon-resistant building codes. However, the map is not intended to be used for determining if a home in a given zone should be tested for radon. Homes with elevated levels of radon have been found in all three zones.

In addition, indoor radon levels vary from building to building. Do not rely on radon test results taken in other buildings in the neighborhood—even ones next door—to estimate the radon level in your building.

Contact your state radon office for information about radon in your local area. The Internet is also a source of information about radon levels in some states.

Where can I get more information about radon issues?

The Radon Hotline is a toll-free number, (800) 767-7236, through which callers can order a brochure on radon. It contains information on ordering a low-cost short-term test kit. In addition, users are instructed to call another numbers, (800) 557-2366, if they wish to speak with an information specialists. They are available to assist callers between 9:00 AM to 5:00 PM (Central) on business days. They can answer specific questions and mail free, single copies of many radon documents, including the EPA booklet, Home Buyer’s and Seller’s Guide to Radon.

Multiple copies of many the EPA documents can be ordered through the EPA’s National Service Center for Environmental Publications (NSCEP), (800) 490-9198, fax (513) 489-8695. 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

Please use the EPA Document Number when ordering from NSCEP. Allow several weeks for delivery.

The EPA also supports operation of National Radon Helpline (800-557-2366) – has information specialists available to assist consumers with more details about radon.

In addition, the EPA also supports operation of the Safe Drinking Water Hotline, (800) 426-4791, which answers questions about radon in drinking water.

Many states provide radon information that is specific to their area. Their contact information is also available on EPA’s web site.

Testing Air for Radon

Why should I test my home for radon?

Radon is widely believed to be the second leading cause of lung cancer. Therefore, the EPA and the Surgeon General along with many agencies around the world recommend testing for radon in all homes below the third floor.

Radon has been found in homes, schools and offices all over the United States. Any home, school or office can have a radon problem. On average, one out of every fifteen U.S. homes has a problem. The only way to know whether or not your home has a radon problem is to test for it.

Who can test a building for radon?

Anyone can use a “do-it-yourself” test kit to check their home or building. The single-use kits are simple to use and are relatively inexpensive.  After being exposed to the buildings air for a  specified time period, usually 48 to 72 hours for short term test kits and 90 to 365 days for long term test kits. Then the kits must be properly sealed and returned to an analytic laboratory.  Radon test kits sometimes are available in hardware stores and other retail outlets. They are also available through the Internet and this sites radon store.

If you are not doing your own testing, a qualified radon professional should be hired. Many people find it preferable to hire a professional when testing is being conducted as part of a real estate transaction, that helps eliminate the question of possible conflict of interest.

Some states require providers of radon measurement services to participate in registration, certification, or licensing programs. In states lacking their own certification or licensing programs, you should hire a professional who participates in the national qualification program for radon professionals.

Call your state radon office to learn about local radon testing requirements and contractors. You can also contact the National Environmental Health Association’s (NEHA) National Radon Proficiency Program at (800) 269-4174 (,  the National Radon Safety Board (NRSB) Program at (866) 329-3474 (, or view the EPA’s website at for more information on radon testing professionals in your area.

What testing protocol should be followed?

The purpose of the measurements, as well as budget and time constraints, dictate the protocol used. However, the EPA and the Surgeon General recommend testing all homes below the third floor for radon. The EPA recommends that for homes, initial measurements be short-term tests placed in the lowest lived-in level.

The protocol for measurements made for the purpose of assessing the need for mitigation (reducing the radon level) is found in the EPA publication, A Citizen’s Guide to Radon. Additional guidance is provided in Section 2 of the EPA book, Protocols For Radon and Radon Decay Product Measurements In Homes.

Protocols for measurements made for real estate transactions are somewhat different. They are described in the EPA document, Home Buyer’s and Seller’s Guide to Radon. Additional guidance is provided in Section 3 of the EPA publication, Protocols For Radon and Radon Decay Product Measurements In Homes.

What’s the difference between short- and long-term radon tests?

Radon levels within a building often change on a day-to-day basis. Highest indoor levels are often found during the heating season. Weather conditions, operation of furnaces and fireplaces, and opening/closing of windows and doors are among the factors that cause these patterns.

Short-term test kits are the quickest way to test. These kits should remain in the building from two to 90 days, depending on the device. Testing must be conducted for at least 48 hours. Some devices must be exposed for a longer time. 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.

The EPA recommends that for homes, initial measurements be short-term tests placed in the lowest lived-in level. Short-term testing under closed-building conditions helps to ensure that residents quickly learn if a home contains very high levels of radon. 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. If testing for 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.

Because radon levels may fluctuate by as much as a factor of two or three, additional testing is sometimes recommended to better assess the average radon level. Though short-term tests are sometimes used, long-term tests are often recommended.

Long-term tests remain in your home for more than 90 days. A long-term test gives a reading that is more likely to reflect the building’s year-round average radon level than a short-term test. Because of season variations in radon levels, the closer the long-term measurement is to 365 days, the more representative it will be of annual average radon levels.

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, the EPA recommends the problem be corrected.

What kinds of radon test devices are used?

For short-term testing there are two primary types.

1. Passive devices do not need power to function. This group includes alpha track detectors, charcoal canisters, and charcoal liquid scintillation detectors. Some charcoal technologies are prone to interference by high humidity, so may not be appropriate for use in all building conditions. These test devices are readily available at many drug, hardware, and other stores, the Internet, and through our online radon store. Electret ion chamber detectors, another type of short-term test device, are usually only available through laboratories. After being used, passive devices are returned to a laboratory for analysis.

2. Active devices require power to function. This group consists of different types of continuous monitors and continuous working level monitors. One particular model, the Safety Siren Pro Series 3 Radon Gas Detector, is specifically designed for home owner use. It is as simple to use as plugging in a carbon monoxide detector. It has a LED display of the average radon level that is continuously updated every hour and it has an alarm to signal if the average radon level goes above 4 pCi/L. These little units are great, I have purchased a couple of dozen the last several years to use for diagnostic testing in radon mitigation. These are excellent if you have a radon mitigation system which should be tested every 2 years, these can be left plugged in for a year to get a long term radon level, or moved from room to room, loaned out to family or neighbors. The list price for the Safety Siren Pro Series 3 Radon Gas Detector is $169 we sell them online for $129 that includes free shipping.

Some of the professional active monitors cost from $850 to $2000 and few much more then that. Many of those provide data of the high and low ranges at hourly intervals within the test period. Some are designed to detect and deter interference. However, they usually require operation by trained testers. These tests often cost more than passive testing.

Technical information on use of various devices used to measure radon or radon decay products is found in the EPA publication, Indoor Radon and Radon Decay Product Measurement Device Protocols.

Where should home testing be done?

The EPA recommends that testing be done in the lowest level of the home suitable for occupancy. This typically represents an area where greatest radon level may occur. Ideally, the test should be conducted in a regularly used room on that level, such as a living room, playroom, den, or bedroom. Avoid testing in a kitchen, bathroom, laundry room, or hallway. High humidity and drafty conditions can bias results from some test devices. Do not disturb the devices while they are sampling. Doing so may alter their results, so they should be placed out of the way.

In very well insulated or efficient, well sealed homes I have seen a number of homes where the highest radon level was on the second floor. This is usually due to a basement being a little more drafty than the finished upper levels that are sealed so well the radon becomes trapped. If the lowest occupied level is not used much, consider also testing a higher-use area. This may help you to better estimate your long-term exposure.

Because most indoor radon comes from naturally occurring radon in the soil, high indoor levels are more likely to exist below the third floor. This is why the EPA recommends testing all homes below the third floor. In some cases, high radon levels have been found at or above the third floor, and even high rise buildings many stories up due to radon given off from the concrete in the floors and ceilings or radon movement through elevators or other air shafts in the building. If you are concerned about this possibility, you may decide to test for radon above the third floor also.

More information on site selection can be found in the EPA publication, Protocols for Radon and Radon Decay Product Measurements in Homes.

If a test result is less than 4 pCi/L (0.02 WL), what should be done next?

If the result of an initial short-term measurement is below 4 pCi/L, or 0.02 WL, a follow-up test is not necessary. However, since radon levels change over time, you may want to test again sometime in the future, especially if use patterns change and a lower level of the building becomes occupied or used more often. Renovations, changes in ventilation, earthquakes, settling of the ground beneath the building, and other changes may cause indoor radon exposures to change.

The EPA states that even if the level is below 4 pCi/L you may want to consider lowering the radon if it is above 2 pCi/L. This would be something to consider if there is someone that is in the house most of the time, like pre-school children and home bound seniors, etc.

If an initial short-term test result is 4 pCi/L (0.02 WL) or higher, what should be done next?

The EPA recommends a follow-up measurement be used to confirm whether radon levels are high enough to warrant mitigation. There are two types of follow-up measurements that may be conducted. The choice depends, in part, on the results of the initial test.

An initial measurement result of 10 pCi/L (or 0.05 WL) or greater should be quickly followed by a second short-term test under closed-building conditions. If the average of the initial and second short-term results is equal to or greater than 4 pCi/L (0.02 WL), radon mitigation is recommended. If the average of the short-term test results is less than 4 pCi/L, consider testing again sometime in the future.

If the result of the initial measurement is between 4 pCi/L (or 0.02 WL) and 10 pCi/L (or 0.05 WL), the follow-up test may be made with either a short-term or a long-term method. If a long-term follow-up test result is 4 pCi/L (0.02 WL) or higher, the EPA recommends remedial action. If the long-term follow-up test result is less than 4 pCi/L, consider testing again sometime in the future.

If a short-term follow-up test is done and the result is 4 pCi/L or higher, radon mitigation is recommended. If the average of the initial and follow-up short-term tests is less than 4 pCi/L, consider testing again sometime in the future.

In certain instances, such as may occur when measurements are performed in different seasons or under different weather conditions, the initial and follow-up tests may vary by a considerable amount. Radon levels can vary significantly between seasons, so different values are to be expected.

Radon Resistant Construction

What does radon resistant construction incorporate?

The techniques vary for different foundations and site requirements, but the basic elements are:

A.     Gas Permeable Layer—This layer is placed beneath the slab or flooring system to allow the soil gas to move freely underneath the house. In many cases, the material used is a 4-inch layer of clean gravel.

B.     Plastic Sheeting—Plastic sheeting is placed on top of the gas permeable layer and under the slab to help prevent the soil gas from entering the home. In crawlspaces, the sheeting is placed over the crawlspace floor.

C.     Sealing and Caulking—All openings in the concrete foundation floor are sealed to reduce soil gas entry into the home.

D.     Vent Pipe—A 3- or 4-inch gas-tight or PVC pipe (commonly used for plumbing) runs from the gas permeable layer through the house to the roof to safely vent radon and other soil gases above the house.

E.      Junction Box—An electrical junction box is installed in case an electric venting fan is needed later.

Ways to reduce radon in your home are discussed in the EPA’s publication, Consumer’s Guide to Radon Reduction.

When should radon-resistant construction be considered?

Find out if you are buying a home in a high radon area.  The EPA’s map of radon zones indicates areas having the greatest potential for elevated indoor radon readings. Homes in places with high potential, called Zone 1 areas, should be built with radon-resistant features. Also contact your state radon office to learn whether radon-resistant features are recommended or required in your area.

If you are planning to make any major structural renovation to an existing home, such as converting an unfinished basement area into a living space, it is important to test the area for radon before you begin the renovation. If your test results indicate a radon problem, radon-resistant techniques can be inexpensively included as part of the renovation. Because major renovations can change the level of radon in any home, always test again after work is completed.

What are the benefits of radon-resistant construction?

Radon-resistant techniques are simple and inexpensive. Besides reducing radon levels, they also lower concentrations of other soil gases and decrease moisture problems. They make a home more energy efficient, and can save an annual average of $65 on energy costs.

How much does it cost to reduce radon in an existing home?

If a home with a vent system is found to have an elevated radon level, a fan can be added at a low cost. The total cost is much lower than adding the entire system after the building is completed. The average cost to install radon-resistant features in an existing home is $800 to $2,500.

About 1995 the EPA estimated that the national average cost for an active radon mitigation was $1200. In my area of Central New York, most radon mitigation system are install for between $1000 and $1200. The average cost to install radon-resistant features in a new home during construction is $350 to $500 (a 128% to 400% saving).

Who should I hire to install radon-resistant features?

Talk to your builder about installing a radon-reduction system during major renovations or new construction. Radon-resistant features can be easily and inexpensively installed with common building practices and materials. There is usually no need to hire a special contractor or architect. Many builders already incorporate some of these steps in the construction of their houses to control moisture or increase energy efficiency.

The EPA’s publication, Radon Mitigation Standards, provides radon mitigation contractors with uniform standards that will ensure quality and effectiveness in the design, installation, and evaluation of radon mitigation systems in detached and attached residential buildings three stories or less in height.

Should a home built with radon-resistant features be tested?

Yes. Every new home should be tested for radon after occupancy. Test your home even if it has the radon resistant features. Test kits are inexpensive and may be purchased at your local hardware store.

Reducing Radon or Radon Mitigation (also called Radon Remediation)

What is a radon mitigation system?

A radon mitigation system is any system or steps designed to reduce radon concentrations in the indoor air of a building.

The EPA recommends that you take action to reduce your home’s indoor radon levels if your radon test result is 4 pCi/L or higher.

What are the benefits of radon mitigation?

Radon reduction systems work. In most new homes, use of radon-resistant features will keep radon levels to below 2 pCi/L. Some radon reduction systems can reduce radon levels in your home by up to 99.9 percent.

A well installed Radon Mitigation Systems is a capital improvement. They not only make your home more safe but also increase the value of your home and its marketability. When selling your home in an area known to have high radon, an active radon mitigation system can alleviate the radon concerns of buyers.

Homeowners should consider correcting a radon problem before making final preparations to sell a home. This often provides more time to address the problem and find the most cost-effective solution. In addition, the current occupants—not just the buyer’s occupants—will reap the benefit of reduced risk.

What can be done to reduce radon in a home?

Your house type will affect the kind of radon reduction system that will work best. Houses are generally categorized according to their foundation design. For example: basement, slab-on-grade (concrete poured at ground level), or crawlspace (a shallow unfinished space under the first floor). Some houses have more than one foundation design feature. For instance, it is common to have a basement under part of the house and to have a slab-on-grade or crawlspace under the rest of the house. In these situations a combination of radon reduction techniques may be needed to reduce radon levels to below 4 pCi/L.

There are several methods that a contractor can use to lower radon levels in your home. Some techniques prevent radon from entering your home while others reduce radon levels after it has entered.  The EPA generally recommends methods that prevent the entry of radon.

In many cases, simple systems using underground pipes and an exhaust fan may be used to reduce radon. Such systems are called “sub-slab depressurization,” and do not require major changes to your home. These systems remove radon gas from below the concrete floor and the foundation before it can enter the home. Similar systems can also be installed in houses with crawl spaces. Radon contractors use other methods that may also work in your home. The right system depends on the design of your home and other factors.

Sealing cracks and other openings in the floors and walls is a basic part of most approaches to radon reduction. Sealing does two things, it limits the flow of radon into your home and it reduces the loss of conditioned air, thereby making other radon reduction techniques more effective and cost-efficient. The EPA does not recommend the use of sealing alone to reduce radon because, by itself, sealing has not been shown to lower radon levels significantly or consistently. It is difficult to identify and permanently seal the places where radon is entering. Normal settling of your house opens new entry routes and reopens old ones.

Any information that you may have about the construction of your house could help your contractor choose the best system. Your contractor will perform a visual inspection of your house and design a system that is suitable. If this inspection fails to provide enough information, the contractor will need to perform diagnostic tests to help develop the best radon reduction system for your home. Whether diagnostic tests are needed is decided by details specific to your house, such as the foundation design, what kind of material is under your house, and by the contractor’s experience with similar houses and similar radon test results.

How much does it cost to reduce radon in an existing home?

The cost of making repairs to reduce radon is influenced by the size and design of your home and other factors. Most homes can be fixed for about the same cost as other common home repairs, like painting or having a new hot water heater installed. The average cost for a radon contractor to lower radon levels in a home has been about $1,200 since the mid 1990′s, although this can range from $500 to about $2,500. Your costs may vary depending on the size and design of your home and which radon reduction methods are needed. In central New York 90% of the systems I install cost below $1200. Most radon contractors will give free estimates.

Who should I hire to correct a radon problem?

The best answer for this is to educate yourself and make an informed decision. Lowering high radon levels requires technical knowledge and special skills. You should use a contractor who is trained to fix radon problems, but PLEASE take careful note of the following paragraphs.

As a licensed Home Inspector, I have inspected hundreds of homes with radon mitigation systems in the past decade and I’ve also as a radon mitigation  contractor I’ve repaired many systems installed by other companies in central New York. I observed that many radon systems were improperly installed, and some were quite unsafe and/or not working at all. In New York State there is no licensing or certification requirement or regulatory oversight for radon mitigation. Below is a partial listing of my findings:

  • Above 80% of systems are installed with thin wall pipe that does not meet the EPA Radon Mitigation Standards. (See picture below to the right to see the difference in strength between thin wall schedule 20 PVC pipe and the proper schedule 40 PVC pipe.)
  • More than 50% of radon systems are not properly labeled as per EPA mitigation standards, many are not labeled at all.
  • About 10% are installed with serious safety problems i.e. fan motors in living areas, fans used that are not designed for radon gas, improper wiring or switching, vent pipe joints not glued and/or loose (sometimes pipes completely disconnected),
  • Improper installation and or sealing, resulting in back draft and carbon monoxide leaking from gas appliances-which were not *tested for back drafting.
  • Often times the vent pipes terminate, spewing radon gas too close to the ground or too close to windows or doors, or not above the roof line as per EPA standards. A potentially serious hazard, as high levels radon gas is pulled from the ground and may re enter the house or be exhausted into an area where people or pets will breathe the radon laden air.
  • In many radon systems it is observed that inferior materials are used, other than those specified by the EPA, either out of ignorance, lack of concern and or in an effort to increase profit by cutting material costs. The EPA specifies proper materials for their durability and long term safety. (The use of proper materials will often cost double or triple the price of inferior materials used on many jobs.)
  • Above 90% of penetrations through garage fire walls, do not have fire collars installed (cost about $35 each) a violation of fire code.
  • Many systems have no manometer installed as per EPA. (For pictures/examples of unsafe radon systems:

The city of Syracuse requires a permit to install a radon mitigation system in city limits, this fact is not advertised or enforced and not one single radon system has been inspected by the Syracuse HVAC code enforcement department as of this writing.  I spoke with one of the seinor code enforcement officials who checked this out last week, who told me the code enforcement inspectors do not know what is required for a proper radon system. I don’t expect that to change soon, there are only two inspectors, they can’t even begin to keep up with HVAC inspections, let alone take on a whole new field of oversight and education.

Since most homeowners do not know what a proper radon system should include, some radon mitigation contractors, including many of the NY State listed radon mitigation contractors (who hold certifications) knowingly use substandard materials and installation methods that do not meet the Radon Mitigation Standards set by the EPA and many other radon agencies standards. For a few of these contractors, this may be done out of ignorance but for most it is simply cutting corners, to increase their profits and get the job done quicker. No wonder most of them do not properly label the systems or include contact information or provide a system folder describing the function maintenance and warranty of the system, all of which are required by the EPA Radon Mitigation Standards.

The EPA stopped operating its National Radon Proficiency Program (RPP) on October 1, 1998. That program was designed to test radon contractors and provide a measure of quality control. The RPP is now privately run. See the EPA’s Web site regarding the RPP for information on how to identify qualified contractors.

Many states certify or license radon contractors. New York State does not. You can call your state radon office for information about qualified service providers in your state.

If you plan to fix the problem in your home yourself, you should first contact your state radon office for the EPA’s technical guide, “Radon Reduction Techniques for Detached Houses.”

Will any more testing be needed after a radon mitigation system has been installed?

Most radon reduction systems include a monitor that will alert you if the system needs servicing. However, regardless of who fixes the problem, you should test your home afterward to be sure that radon levels have been reduced. This test should be conducted no sooner than 24 hours nor later than 30 days following completion and activation of the mitigation system(s). Potential conflict of interest can be avoided by using an independent tester.

In addition, it’s a good idea to retest your home sometime in the future to be sure radon levels remain low. Testing should be done at least every two years or as required or recommended by state or local authority. Retesting is also recommended if the building undergoes significant alteration.

Are funds available to reduce high radon levels in rental housing?

There are some federal programs that might be used to help fund radon reduction in homes that are affordable to limited income families. These programs generally give money to local agencies or groups, which then fund the work. Some examples are:

Community Development Block Grant (CDBG) program—funds rehabilitation and repair of affordable housing. For more information, call the U.S. Department of Housing and Urban Development (HUD) at (202) 708-3587.

“203k” program—funds rehabilitation and repair of single family homes. For more information, call HUD at (202) 708-2121.

Environmental Justice Grants—funds community-based organizations and tribal governments addressing environmental concerns of people of color and low income communities. For more information, call the EPA’s Office of Environmental Justice at (800) 962-6215.

Some states have governmental programs that can provide loans for radon reduction work in limited income housing. Some community groups are raising funds from private companies and foundations to pay for radon reduction in limited income homes.

To find out more about federal and state programs, or about how community groups have developed local projects to fix radon problems, owners and residents can contact your state radon office.

Radon in Water

How does radon get in water?

When the ground produces radon, it can dissolve and accumulate in water from underground sources (called ground water), such as wells. When water that contains radon is run for showering, washing dishes, cooking, and other uses, radon gas escapes from the water and goes into the air. Some radon also stays in the water.

Radon can be a concern if your drinking water comes from a well that draws from an underground source, though not all water from underground sources contains radon. If you get your water from a public water system that serves 25 or more year-around residents, you will receive an annual water quality report. These water quality reports include information on what is in your water, including radon if it has been tested.

Radon from lakes, rivers, and reservoirs (called surface water) is of much less concern. Most of the radon is released from the water before it enters the distribution system.

Does radon in drinking water pose a risk?

In most cases, radon entering the home through water will be a small source of risk compared with radon entering from the soil. The EPA estimates that indoor radon levels will increase by about 1 pCi/L for every 10,000 pCi/L of radon in water. Only about one to two percent of indoor radon in air comes from drinking water.

Based on a National Academy of Science report, the EPA estimates that radon in drinking water causes about 168 cancer deaths per year: 89 percent from lung cancer caused by breathing released to the indoor air from water and 11 percent from stomach cancer caused by consuming water containing radon.

Radon gas can enter the home through well water. It can be released into the air you breathe when water is used for showering and other household uses. Research suggests that swallowing water with high radon levels may pose risks, too, although risks from swallowing water containing radon are believed to be much lower than those from breathing air containing radon.

While radon in water is not a problem in homes served by most public water supplies, problems have been found in well water. If you’ve tested the air in your home and found a radon problem, and your water comes from a well, contact a lab certified to measure radiation in water to have your water tested. Call the EPA’s Safe Drinking Water Hotline, (800) 426-4791, to get information on locating a certified lab.

If you’re on a public water supply and are concerned that radon may be entering your home through the water, call your public water supplier.

Should drinking water be tested for radon?

Because radon in indoor air is the larger health concern, the EPA recommends that you first test the air in your home for radon before testing for radon in your drinking water.  The EPA and the Surgeon General recommend testing all homes for radon in indoor air (and apartments located below the third floor). The EPA recommends that you take action to reduce your home’s indoor radon levels if your radon test result is 4 pCi/L or higher.

If you have tested the air in your home and found a radon problem, you may also want to find out whether your water is a concern. If you get water from a public water system, find out whether it comes from a surface (river, lake, or reservoir) or a ground water (underground) source.

If the water comes from a surface water source, most radon in the water will be released to the air before it reaches your tap. If the water comes from a ground water source, call your water system and ask if they’ve tested the water for radon. If so, ask for their Consumer Confidence Report.

If you have a private well, the EPA recommends testing your water for radon. The Safe Drinking Water Hotline, (800) 426-4791, can provide phone numbers for your state laboratory certification office. You can also call the National Radon Hotline, (800) 767-7236, for your state radon office’s phone number. Your state laboratory certification office or state radon office can direct you to laboratories that are able to test your drinking water for radon.

What do the results of a radon water test mean?

Estimate how much the radon in your water is elevating your indoor radon level by subtracting 1 pCi/L from your indoor air radon level for every 10,000 pCi/L of radon that was found in your water. (For example: if you have 30,000 pCi/L of radon in your water, then 3 pCi/L of your indoor measurement may have come from radon in water.) If most of the radon is not coming from your water, fix your house first and then retest your indoor air to make sure that the source of elevated radon was not your private well. If a large contribution of the radon in your house is from your water, you may want to consider installing a special water treatment system to remove radon. the EPA recommends installing a water treatment system only when there is a proven radon problem in your water supply.

What levels of radon in water should I be concerned about?

There is currently no federally-enforced drinking water standard for radon.

The EPA does not regulate private wells, but is proposing to regulate radon in drinking water from community water suppliers (water systems that serve 25 or more year-round residents). the EPA proposed the rule in October 1999 and plans to finalize it in August 2000.

The EPA is proposing two options:

•          The first option would require community water suppliers to provide water with radon levels no higher than 4,000 pCi/L. Because about 1/10,000th of radon in water transfers to air, this would contribute about 0.4 pCi/L of radon to the air in a home. This level will be permitted if the state also takes action to reduce radon levels in indoor air by developing the EPA-approved, enhanced state radon in indoor air programs (called Multimedia Mitigation Programs). This is important because most of the radon you breathe comes from soil under the house. This option gives states the flexibility to focus on the greatest problems, encouraging the public to fix radon in indoor air problems and to build homes that keep radon from entering.

•          A second option is provided for states that choose not to develop enhanced indoor air programs. Community water systems in those states will be required to reduce radon levels in drinking water to 300 pCi/L. This amount of radon in water contributes about 0.03 pCi/L of radon to the air in your home.

Even if a state does not develop an enhanced indoor air program, water systems may choose to develop their own local indoor radon program. This will require them to meet a radon standard for drinking water of 4,000 pCi/L. This option enables overall risks from exposure to radon, both through air and water, to be reduced.

How is radon removed from water?

Radon can be removed from water by using one of two methods: aeration treatment or granular activated carbon (GAC) treatment.

Aeration treatments involve bubbling air through the water. This helps to strip radon from the water. An exhaust fan is used to vent the radon outdoors.


GAC treatment filters water through carbon. Radon attaches to the carbon and leaves the water free of radon. GAC filters tend to cost less than aeration devices. However, radioactivity collects on the filter and may cause a handling hazard and require special disposal methods for the filter.

For more information on aerators and GAC filters, you should contact two independent, non-profit organizations: NSF International at (800) 673-8010 and the Water Quality Association at (630) 505-0160.

In either treatment, it is important to treat the water where it enters your home (point-of-entry device) so that all the water will be treated. Point-of-use devices, such as those installed on a tap or under the sink, will only treat a small portion of your water and are not effective in reducing radon in your water.

It is important to maintain home water treatment units because failure to do so can lead to other water contamination problems. Some homeowners opt for a service contract from the installer to provide for carbon replacement and general system maintenance.

Where Does Radon Come From?

Radon comes from the natural radioactive decay of radium and uranium found in the soil and rock underground. The amount of radon in the soil depends on the geology, the type of rock and soil which can often vary greatly from one house to the next. Radon levels in the soil range from a few hundred to several thousands of pCi/L up to more than a million pCi/L in some uranium mines. The major source of indoor radon comes from the soil. The rate at which it enters a building depends on the weather, soil porosity, soil moisture, and the suction within the house. Less common sources of radon inside a home are water and sometimes building materials like, concrete, cement blocks, dry wall board and plaster. In some high radon areas well water can be the source of very high levels of indoor radon.


You have heard “hot air rises”, well houses act like large chimneys, as the air in the house warms, it rises up through the house, through the ceiling and out the upper floor window glass and walls. The purpose of insulation and air sealing is to stop this natural process of heat loss.This process called the “stack effect” or “chimney effect” creates a small amount of suction at the lowest level of the house, and actually pulls the air from the soil into the house. On cold winter days you can also feel cold drafts which are cold air being sucked into the house through small cracks and openings. This same suction is what pulls the radon out of the soil and into the house.

You might think caulking the cracks and the openings in the basement floor will stop the radon from entering the house. However, scientific studies show, it only takes enough unsealed cracks or pin holes in the caulking to equal a hole 1/2″ in diameter to let all the radon in. Also radon can be pulled right through a concrete floor, even if it has no cracks in it. Caulking cracks and joints will slow down the radon entry but will not stop it, and often the radon levels remain unchanged. Add to this the fact that, air in soil is under positive pressure compared to the atmosphere, so in addition to the house sucking in radon, the positive air pressure underground is also pushing radon up to the surface. Radon is a gas and simply follows the path of least resistance.


The only way to know is conduct a radon test. The Surgeon General states that every home in the united states should be tested including all living quarters (apartments and housing facilities, etc.) up to the second floor level. Every part of the country has at least some dangerously high levels of radon. Just because you live in a high radon area does not mean your home has high radon. There can be several homes on a street, of similar age and construction quality all with high radon levels and right in between them a home with low radon, and visa verse. 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


There are Two General Ways to Test for Radon:


There are also Two General Types of Radon 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,” “electric 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, like in a real estate purchase, a short-term test during the home inspection can be followed by a second short-term test to confirm results at another time. Short term tests can help give a quick assessment of whether there may be a need to fix your home.

Long-term tests remain in your home for more than 90 days. “Alpha track” and “electronic” 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.


It depends on your needs. If there is electricity available, the best may be a combination of both long and short term tests. This can be accomplished with an electronic radon monitor designed for home use. This simple to use devise was designed specifically for homeowners and works similarly to a carbon monoxide detector. You just plug it in, and within 48 hours it gives the average radon reading on a LED digital display. You can reset it to do another short term test or leave it plugged in continuously for long term readings. It also has an hourly alarm if the average radon level is 4.0 pCi/L or higher.

It is a good idea to test different rooms in the house on all levels. The amount of radon can vary greatly from room to room and from season to season. One electronic monitor will pay for itself quickly if you plan to do a few tests or more. Also it can be loaned out to friends and family to test their homes. These are also great if you have a radon system installed in your home. The EPA recommends that all homes with active radon mitigation systems running, test the home every 2 years. Just keep this little monitor plugged in and it will serve as an audible alarm it the mitigation system fails to keep the radon level below 4 pCi/L


Do-it-yourself radon test kits are very inexpensive, they can be purchased for $10 to $30 and sometimes that includes the laboratory fee and returned test results. Some kits require an additional laboratory fee, and there is a small shipping charge with most kits of a couple of dollars. If you decide to hire a radon testing professional or radon testing firm, the cost of a single radon test is usually between $100 and $200. They will set the test devise, pick up the test device and provide written or email test results.


Fortunately, there are other extremely effective means of keeping radon out of your home. Radon mitigation also called radon remediation is a process where a designed system is installed to remove radon gas or lower the level of radon in a home or building to an acceptable level, usually below 4.0 pCi/L. Throughout the country, several million people have already tested for radon. Some houses tested as high as 2,000-3,000 pCi/L; yet, there hasn’t been one house that could not mitigate the radon to an acceptable level.


The EPA reported in the 1990′s that the average cost of a radon mitigation system in the United States was $1200. There are many methods of radon mitigation. In central New York the average system costs about $1200. Some can be installed for half that and some cost twice that. Some jobs are difficult or large and may require a combination to different techniques or more than one system.


Radon mitigation requires a well rounded set of skills but is not outside reach of some enthusiastic do-it-yourselfers. However be sure of what you are getting into. It is not as easy as it appears. Some mitigation jobs can prove to be very difficult. Some are quite tricky, like boring large holes in concrete floors that have radian heating pipes in them. I would have to say a radon mitigatation system is one of the most challenging home improvements that there is, it requires at least intermediate skill level in plumbing, electrical, carpentry, and masonry or concrete work. The tools are large and expensive, and they can cause injury easily. Drilling large 4 1/2 to 5 1/2 inch holes with a very powerful drill through a wooden beam or concrete floor or cement wall is not easy, if the drill catches and torques your wrist or shoulder you might be out of commission for a few days or more.

Some relatively easy and minor radon mitigation techniques (to lessen the harmful effects) that can be done by a non-professional are:

  • Increase the ventilation in your home (open windows and doors whenever possible.)
  • Limit the amount of time anyone spends in the areas of your home which have the greatest radon concentration (for example, the basement.)
  • If your home has a crawl space, keep the crawl space vents on all sides of the house fully open all year.
  • Stop smoking and discourage smoking in your home.


Underground well water can transport the radon from the soil into the house, when taking a shower, doing laundry, or washing dishes. The EPA says it takes about 10,000 pCi/L of radon in water to contribute 1.0 pCi/L of radon in air throughout the house. The ratio of radon in water to radon in bathroom air while showering can be much higher, typically from 100 to 1; to about 300 to 1. Radon can also enter the body through drinking water in small amounts is not a concern but very high levels could contribute to stomach and other cancers. The average Colorado well tests about 3,000 pCi/L with one well testing more than 3,000,000 pCi/L. Some areas of New York are known to have high radon in well water, such as the towns of Hamilton and Tully in central New York.


If your water comes from a municipal reservoir supply, you need not worry about radon in the water. When radon in water is stored in a reservoir for more than 30 days, the radon decays away to practically nothing. Every 3.825 days half the radon disappears through natural radioactive decay.


Scientists believe radon exposure is the second leading cause of lung cancer. When radon decays, it shoots off alpha particles. These are small, heavy, electrically charged, sub-atomic particles consisting of two protons and two neutrons. If an alpha particle strikes the chromosomes in a lung cell, it could alter the DNA, the way that cell reproduces. Our bodies immune system should recognize and destroy these mutant cells before they can multiply over the next 10 to 20 years into a recognizable cancerous growth.

Some peoples immune system is better than others. Because of these inherent differences, radon doesn’t affect everyone the same.


According to the following EPA radon risk chart, radon is a serious health problem.

If 1,000 people were exposed to this level over a life time who are:

Radon Level….Smokers………….Never Smokers

20 pCi/L….14% or135 people…..0.8% or 8 people could get lung cancer

10 pCi/L…..7% or 71 people…..0.4% or 4 people could get lung cancer

4 pCi/L……3% or 29 people…..0.2% or 2 people could get lung cancer

2 pCi/L……2% or 15 people…..0.1% or 1 person could get lung cancer


There is little disagreement that breathing the hundreds of pCi/L of radon that caused thousands of uranium miners to get fatal lung cancer is definitely harmful. Many scientists disagree with the EPA about what the level of radon should be before it should be reduced.

The EPA studied the lung cancer risk of uranium miners exposed to 400 pCi/L. They assume the risk of a home owner exposed to 4 pCi/L to be one hundredth as much. Based on this assumption, the EPA guideline level of 4 pCi/L represents a much greater risk than allowed for other environmental pollutants.

Other scientists have tested more than 70,000 homes across the United States. This study shows the counties with the highest average radon levels had the lowest incidence of cancer. Perhaps, breathing the low levels of radon found in the home environment, might not be harmful. Neither study fully accounts for all the different confounding factors that can cause cancer. The truth probably lies somewhere between these two theories.


In 1988 the United States Congress passed legislation, directing the EPA to work toward a long term national goal, “The air within buildings in the United States should be as free of radon as the ambient air outside of buildings.” Real estate agents that are hired and paid by the sellers, represent the sellers economic interests, in the sale of their house. Even a buyer’s Real estate agent has a vested interest, their commission, in you buying the home. Understandably, you might get two completely different opinions about radon, depending whether you ask the EPA, or your real estate agent. If you have hired a radon testing professional or home inspector to test for radon, and explain the test results. They will offer their “most often” unbiased opinion on the subject, and guidance on a prudent course of action. Remember “buyer beware”.


The following represents my opinion and is the recommendations of many US state and county health agencies and several other sources.

A.  If the the house tests above 100 pCi/L in the living area of the home, it is recommended to move out of the home until a radon mitigation system is installed to significantly reduce the level of radon, preferable to below 4 pCi/L. I would add that, if the weather allows you could open a lot of windows to encourage good fresh air circulation, that could greatly reduce the radon in most homes allowing you to remain in the home until it is fixed; however it would be wise to have a way to test or monitor the radon levels to ensure safety until a system is installed.

B. If the house tests above 20 pCi/L most experts agree it is prudent to install a system that can permanently reduce your families exposure to radon to below 4 pCi/L or better yet below 2 pCi/L.

C. If the house tests below 4 pCi/L most experts agree that there is a relatively low probability of significant health risk at this low level of exposure. However, if the test was done for a real estate sale I recommend retesting the radon levels once you move in, to verify this low reading. Industry surveys show that up to 30% of the radon tests in real estate transactions are subject to some ventilation (by accident or on purpose, i.e. cheating), which would invalidate the radon test results. LET THE BUYER BEWARE. A home inspector in Colorado stated the following “We once tested a house, that measured 168 pCi/L in a child’s bedroom. The selling agent ordered a retest by a tester known to test on the second floor with the windows open. He told my clients the house only measured 3.5 pCi/L and they didn’t have a radon problem. Although he never gave my clients a written report stating this.” I believe there is a lot more fraud in radon testing related to real estate sales than most people would ever realize, you know what is said about the love of money.

D. If the house tests between 4 and 20 pCi/L there is no need for immediate panic, but you will have to make some difficult decisions. About 50% of the houses we test fall in this gray area. The average Colorado home measures 5.9 pCi/L. The national average is 1.5 pCi/L and outside air measures about 0.35 pCi/L. The closer to 4 or 20 pCi/L the easier the decision should be. The most difficult decisions are in the 10 to 12 pCi/L range.


Cigarette smokers should keep their exposure to radon as low as possible. Smokers have eight times the risk from radon as non smokers. Smokers who reduce their radon exposure from 6 pCi/L to 2 pCi/L, will receive as much beneficial risk reduction as the non smoker who reduces their exposure from 34 pCi/L to 2 pCi/L.

If the house was tested in an infrequently used basement. It may have measured a radon level that is two to three times the actual level you are exposed to, spending most of your time upstairs.

You can reduce your families annual radon exposure about 40%, if you open the basement windows a few inches to allow cross ventilation from May till September. This may be appropriate for slightly elevated houses that don’t need year round reductions.

People with young children should be more concerned with the possible consequences of radon exposure 20 years from now than someone in their late sixties or seventies.

Families with a hereditary predisposition of cancer should be more concerned about radon exposure than families who don’t have any history of cancer.

If you work for a company that might transfer you in the future, our employer probably will hire a relocation company to purchase your home. Today, most relocation companies insist that the house test below 4 pCi/L before they will buy it. Some buyers have adopted this position; anything below 4 pCi/L is fine while anything above 4 pCi/L is unacceptable. This unfortunate misinterpretation of EPA guidance, could cause you to pay for a radon mitigation system when selling your home. At this time your family would not receive any benefit from the radon reductions.

The decision, What to do about radon? is a personal choice that only you can make. Some people feel it is best to reduce as many of life’s risks as they can. Other people feel the money spent installing and operating a radon mitigation system on a moderately elevated home could be put to better use, having regular family medical and dental check ups, or making other safety improvements in their home.


If you feel the radon levels are high enough to justify installing a radon mitigation system, we recommend installing a good quality, durable, energy efficient system. All our radon reports testing above 4 pCi/L, include detailed specifications, describing the installation and materials needed to achieve this. It is best to have all mitigation contractors bid on installing the system exactly as specified in this report. All too often the sellers or their agents end up deciding, who will do the work, and how it will be done. Their main concern is that it be installed as cheaply as possible to get the radon levels down below 4 pCi/L for the retest. Often they have the contractor who installed the system, do the retesting to verify it is below 4 pCi/L, before he gets paid. This could create a possible conflict of interest.


* A… Install all fans outside the living area of the house, so all interior piping is under negative pressure. Many contractors find it cheaper and easier to put the fan in the basement near an existing electrical outlet. Often these fans and piping develop leaks. This could allow the system to start pulling the thousands of pCi/L of radon out of the ground and blow it into the basement or crawlspace; thus making the radon levels in the house higher than they where originally.
* B… The high radon concentration air blowing from the fan should discharge above the roof, or at least ten feet from any doors, windows or decks. No one wants to breathe hundreds or thousands of pCi/L coming from these fans.
* C… Dig the suction pit under the floor as large as possible, or make sure it intersects the void beneath a grade-beam foundation.
* D… Seal crawlspaces with a gas membrane, made of cross-laminated polyethylene, placed between two layers of 30 lb. tar paper, to protect it from damage. Make sure the membrane is tightly fastened to the foundation walls, with plywood strips and sealed with industrial grade urethane caulking. It is cheaper to install one layer of regular polyethylene directly over the soil, and fasten it to the walls with duct tape, glue or caulking. This method will reduce the radon levels, but the single layer of regular polyethylene gets torn when someone crawls across it. Duct tape or glue usually falls off the wall within a month or so. When this happens, the system will still keep the radon levels down, but the fan will start pulling large amounts of heated air out of the house. The added cold air could subject the crawlspace plumbing to freezing and increase the cost of heating your home as much as $200.00 to $300.00 a year. This unnecessary loss of heat could add up to $20,000.00 to $30,000.00 over the hundred year life of the house. The money saved on the initial installation might not be such a bargain after all.
* E… Caulk the large cracks and joints in the concrete floor slab to prevent unnecessary heat loss.
* F… Install a manometer or warning device to alert you if anything goes wrong with the system.
* G… Permanently label all systems, with the contractors name, phone number, operation and maintenance instructions and a place to note all radon test results. The people living in the house 15 to 75 years from now will need to know what this system is, and why it is needed.


If you are buying a house, this is strictly a matter of negotiation for which there are no hard and fast rules. Some people will choose to follow one of the GOLDEN RULES, Do unto others as you would have them do unto you, or He who has the gold makes the rules. No matter who ends up paying for the system, it is in your best interest that you be the one to select the contractor and specify how the work will be done. If you leave these decisions to others you might not end up with the type of system you want to have. Most contractors will give you a written bid of exactly how much the system will cost when you have them install it. Do not worry if the radon can be successfully reduced; this is a sure thing. In most cases, contractors will guarantee that they will reduce the levels to below 4 pCi/L. Properly installed systems usually get the radon down to below 2 pCi/L and sometimes even below 1 pCi/L. We have tested several houses that originally measured more than 100 pCi/L, that where mitigated to levels below 2 pCi/L.


Most systems are powered by fans that consume less than 90 watts of electricity. That should cost not much more than $5o.00 a year, think of a light bulb in an attic that you may have forgotten to turn off, most people would never notice that added cost of $50 spread out over a year. These fans should last about 11.5 years and presently cost $350.00 to be replaced by a serviceman. Radon fans can be purchased online for about $125 to $195 depending on the fan. If the system is properly installed and well sealed, there shouldn’t be any noticeable increases in the heating bills. However, if the cracks and joints in a finished basement cannot be sealed, the heating cost might increase slightly. Check this on a cold day by feeling the amount of warm air blowing from the fan.


Only in a good way. Especially in an area of high radon often times more than half of the homes in a given area will have elevated radon. Ask yourself would you rather buy a home with a well installed radon mitigation system with very little to no radon or a home with a dangerously high level of radon. Most people would choose home with a working radon system. When radon test results show the home is safe, it becomes a non issue verses a home where the radon level is unknown or dangerously high.


Search this website.

You can call the local Department of Health.
EPA’s Position on Radon
EPA’S Radon Publications

Your local library might have some of the following books.

  • The Indoor Radon Problem…Douglas E. Brookins
  • Radon The Invisible Threat..Michael Lafavore
  • Radon a Homeowner’s Guide (Consumer Reports Books)…Bernard Cohen
  • Radon and its Decay Products…William W. Nazaroff & Anthony V. Niro, Jr.
  • Radiation Hormesis……T.D. Luckey CRC Press
  • Health Risks of Radon and Other Internally Deposited Alpha-Emitters…National Academy Press
  • Health Physics….Pergamon Press The Radiation Protection Journal
  • Radon, Radium and Uranium in Drinking Water…Richard Cothern & Paul A. Rebers
  • Radon in Ground Water…Barbara Graves

    Radiation, Science & Health was organized by independent individuals, knowledgeable of radiation health affects science, and associated public policies. They know that data is misrepresented, and public funds wasted, to support radiation protection policy, that provides no public health benefit.

    Comparing Guideline Levels for Radon in Existing Homes *assuming 50% equilibrium and converting from Working Levels to pCi/l where needed.

    USA EPA (Environmental Protection Agency) 4.0 pCi/l
    Canada 21.6 pCi/l
    Sweden 10.8 pCi/l
    ICRP (International Commission on Radiation Protection) 16.2 pCi/l
    WHO (World Health Organization) 10.8 pCi/l
    NCRP (National Council on Radiation Protection) 8.0 pCi/l

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