Idaho Radon Frequently Asked Questions (FAQ)


Why test for Radon?

Radon is a radioactive gas that has been found in homes all over Idaho. It is produced as a by-product of the natural breakdown of uranium in soil, rock and water, and so eventually gets into the air you breathe. It is the second leading cause of lung cancer.

How long should I test?

The US EPA protocols require that all short-term tests be conducted for a minimum of 48 hours. During the tests, all windows and doors should be kept closed and ventilation and exhaust fans should be turned off. Ideally, however, you should do one year-long test or several short-term tests throughout the year to determine the annual average radon concentration.

What do my readings mean?

The US EPA has set an “action level” of 4 pCi/L (picocuries per liter). Levels equal to or above that amount carry enough risk of lung cancer from exposure to radon to warrant action.

If I am buying a home, what should I do?

If the home has already been tested, decide whether to accept the test results from the seller or ask the seller to do another test by Presidential Inspections (The buyer cannot legally do a test; only the homeowner can). Perform a long-term test after occupying home.

If the home has not yet been tested for radon, test as soon as possible, either by the seller or by a licensed tester and that the test is done in the lowest level of the home which is suitable for occupancy. Consider including provisions specifying who will conduct the test, what type of test to do, costs, additional escrow money for radon mitigation, etc.

Should I buy a house with a radon level greater than 4 pCi/L?

Radon levels can be brought down to well below the EPA “action level” in most houses. Radon mitigation systems that continuously remove radon from the area below a foundation are the most effective.

If I am selling my house, what should I do?

If your home has never been tested perform a radon test as soon as possible. If possible, test before putting your home on the market. Test the lowest level of the home which is suitable for occupancy.

Is it expensive to install a system to remove radon from a house?

A radon mitigation system can be installed for $1000 to $2500. (Varies)

I’ve heard radon is not really a problem. Is this true?

Although some studies dispute the precise number of deaths due to radon, all the major health organizations (like the Center for Disease Control, the American Lung Association, and the American Medical Association) agree with the US EPA’s estimate that radon causes about 17,000 preventable lung cancer deaths every year in the U.S.

How much will it cost to add radon-resistant features during construction of a new home?

According to the US EPA, radon-resistant features typically add only $350 to the cost of building an average house.

How much time does radon remediation take?

According to the US EPA, sealing the foundation is the most time consuming part of radon-resistant construction. The time involved varies from house to house, but is usually just a few hours. This time will be minimized if the house design is simple, with few penetrations in the slab.

Are any special skills or equipment needed to install radon-resistant features during construction of a new home?

Installing radon-resistant features requires only standard plumbing, electrical, and construction skills. A caulk gun for sealing is the only special piece of equipment needed. The material required is available at building supply stores.

I am building a new home. What does my builder have to do to install radon-resistant features during construction?

According to the US EPA, many of the features, which make a house radon-resistant, are already used by builders around the country. First, a layer of gas permeable material (such as gravel) is placed where the house’s slab will be poured. This layer is then covered with plastic sheeting. The concrete slab is poured to minimize cracking, and all floor assemblies in contact with the soil are sealed. Any other places where radon could enter the home are also sealed. The plastic sheeting and sealant block radon’s main entry routes in the house. A length of perforated pipe is installed horizontally beneath the plastic sheeting prior to pouring the slab. This is connected to a vertical, unperforated pipe which extends through the slab and through all floors of the house to vent above the roof. This pipe removes radon from the soil and vents it safely above the dwelling. The gravel beneath the foundation makes it easier for the ventilation system to remove radon, even from the far corners of the foundation. Electrical junction boxes are installed during construction in case a fan is needed to achieve further radon reductions. Normally, suction on the pipe is provided by natural pressure differences within the house. A fan is needed only if the pressure differences cannot lower radon concentrations to acceptable levels.

How can I be sure that radon-resistant techniques work?

According to the US EPA, over half a million radon-resistant homes have been built in the United States, mostly in parts of the country with the highest average radon levels. Researchers have found that radon-resistant features lower radon levels to about half of what they would have been without these features.

How much will it cost me to run a radon-reduction system?

The passive radon-resistant features installed in most houses do not cost anything to run. In fact, sealing the home to prevent radon entry can result in reduced energy costs. While the savings will vary with the climate, size of house and utility prices, the national average is $65 per year in energy costs saved. If a fan-based ventilation system must be used, the cost of electricity to run it will average $70 per year. In addition, fans must typically be replaced at 10 to 15 year intervals at a cost of approximately $150 each. The expected energy savings from sealing the house can help offset these costs.

Is there anything my builder can do in case the radon- resistant features described above do not work?

Sometimes radon levels in a house are too high to be handled by the type of system described above. If this happens, a fan can be added to the system to increase suction on the pipe. This is called “activating” the system. Installing the fan is easy, because of all the required wiring is already in place. The typical cost of a fan is $200, and installation takes approximately 1 hour.

Aside from the health benefits, are there any other benefits to installing radon-resistant features?

Radon-resistant features promote drainage under a house and can reduce moisture problems. As mentioned in the answer to question #15, they also result in energy savings averaging $65 a year. Building a radon-resistant house is also more visually appealing, as the pipe can be hidden in the internal structure of the house. In retrofitting after construction, it is often more difficult to conceal the pipe.

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