Radon Gas Danger in the Home

Inspect for Radon Gas When Purchasing a Home

By Mark J. Donovan




Here in New Hampshire, where its nickname is “The Granite State”, radon is a real concern. The reason for this is that radon, which is a gas, is the second leading cause of lung cancer in the nation. Most rock types contain some trace level of uranium in them, however, granite has an above average uranium content in it.

Consequently virtually every intelligent home buyer in New Hampshire has two types of radon tests done as part of a home inspection. The first test checks for radon gas in the home, and in particular the basement.

The second radon test checks for the presence of radon gas in the water supply.

Radon gas is a chemically inert gas that is odorless and colorless. It also has a high density. As a result, it tends not to mix well with other gasses, e.g. nitrogen and oxygen, and resides in low places, such as in a basement or crawl space. Thus, the reason for testing for radon gas in basements.

Levels above 4pCi/L in the air are considered to be of concern and remedial action should be considered. A radon gas mitigation system typically includes venting the basement and home using a combination of vent pipes and fans that pulls the air from the basement and home. Also any foundation wall cracks should be sealed and any cracks in basement floors should be patched. In addition, the installation of an attic fan is also recommended.

Similarly, radon gas is also soluble in water at certain temperatures. Consequently radon gas can be absorbed and degassed from water with simple changes in the water temperature.

Radon gas pipe being sucked out from under basement slab.

Therefore this is why a home’s water supply should be tested if the home has its own private well. Radon levels above 2K pCi/L in the groundwater supply are considered concerning and should be remediated. Radon gas can be removed from a home’s water supply by aeration treatment or granular activated carbon (GAC) treatment.

Aeration treatment involves spraying or mixing the water supply with air and then venting the air from the water. The GAC treatment involves passing the water supply through a carbon filter where the radon attaches itself to the carbon and thus producing radon free water.

There are two instruments used for detecting the presence of radon gas, the Geiger counter and a gamma sensor (Scintillometer). For home inspections there are two types of air radon tests you can have done. One is a short term test and the other is a long term test. The short term tests costs less and gives you a quick and dirty thumbs up/thumbs down test for the absence or presence of radon in the air. The longer term tests are more expensive but provide accurate levels of the amount of radon gas present in the home or basement.

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For radon water tests, there are kits you can purchase from water testing companies. You simply fill the test bottle with water from your tap and send it in for analysis. The radon water testing company will typically provide you with results in a week.

To find a home inspector in your local area check the American Home inspector Directory, which maintains a national database of home inspectors. Similarly you can find a home inspector via Renovation Expert’s national database of contractors and home inspectors. Simply fill out their free form and 3 to 4 home inspectors in your local area will contact you. There is no charge or obligation to use this service or any one of the home inspectors.


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