What is Radon?
Why should I be concerned?
It has been shown in carefully controlled studies on animals, on hard-rock miners, and most recently confirmed in residential case-control studies, that the effects of the radon decay products (due to prolonged exposure to elevated levels of radon) can significantly increase the potential of lung cancer. Radon is regarded as a Group A carcinogen; that is, it is known to cause cancer in humans with prolonged exposure. Many buyers are concerned about their health risk, as well as property resale value and want to test for and correct radon concerns. The United States Environmental Protection Agency and Surgeon General recommend that people not have long-term exposures in excess of 4.0 pico Curies per liter (pCi/L).
If I find a home with a radon problem should I look for another home?
The presence of high levels of radon should not keep you from buying the home of your dreams. If a properly performed test indicates an elevated level of radon in the home you wish to purchase, it is likely other homes in the same area will have elevated radon. So, if you like the house, consider taking a reasoned approach that will confirm levels and reduce the radon. Perhaps the best news about radon is that radon can be reduced, either before you buy the home, or after you buy it and move in. Of all the problems a house may have, radon is one of the easiest to identify and fix!
Over the last 15 years, reliable testing devices and methods have been developed to determine indoor radon exposures. When using approved measurement devices, you can either determine the radon potential over a short period of time, or an average of radon exposure over a longer period of time.
This is a short-term test, typically 2-5 days. It is conducted under closed building conditions 12 hours prior to and all during test. The test device is deployed on the lowest occupiable level of the home. This is commonly used at time of resale.
This is a long term test, at least 91 days, up to one year. It is conducted under normal lived-in conditions without special closed building conditions. The device is deployed on lowest occupied level of home. It is commonly used outside of a real estate transaction, or used as the basis of escrow fund release, especially if a short-term test has shown results between 4 and 10 pCi/L.
Yes, radon can dissolve in the groundwater and be released into the air of the home when it is used for showers, laundry, and other purposes. The concern with radon in water is not widespread and is primarily associated with homes whose water supplies are from wells or public water supplies that use groundwater. The major concern is not with drinking the water, but rather with the additional amount of radon added into the breathing space beyond that which comes from the soil. Normal radon in air tests will measure this contribution, if the house is occupied during testing. It takes a lot of radon in the water to have a measurable effect on the indoor radon concentrations. As a rule of thumb, it takes 10,000 pCi/L in the water to add one additional pCi/L of radon in the air. So always test the air first, before testing or becoming concerned with radon in the water. Your radon testing professional should be able to provide guidance.
Radon is mitigated by installing a system that will draw the radon-laden soil gas from beneath the foundation and exhaust it outside of the building, far enough away from windows and other openings that it will not reenter. A mitigation system typically consists of a plastic pipe connected to the soil either through a hole in a slab, via a sump lid connection, or access beneath a plastic sheet in a crawl space. Attached to the pipe is a quiet, continuously operating fan that discharges the radon outdoors.
The type of mitigation system is a function of the construction of the home, rather than the radon concentrations that exist. A home with more than one foundation can present challenges to collecting the soil gas from under all portions of the building. However, talented mitigation contractors typically can connect multiple systems together so that only one fan system is required. Crawlspace foundations can be more costly, since the contractor needs to install a high density plastic sheet over the soil, seal it to the walls and then route the piping to the fan. However, the added benefit of reducing moisture in the crawlspace, in addition to reducing radon, can be a real plus.
- Average U.S. installation cost: $1,200
- Expected life span of fan: 11 years
- Fan replacement cost: $145-300
- Periodic maintenance: none
The cost of a mitigation system is a function of the extra effort taken by the contractor to conceal the system and to maintain the aesthetic value of your home. Although a system routed up the outside of the house will reduce radon quite well, it may not be as aesthetically pleasing as one that was routed through the interior of the house with trim installed to conceal it. An increasing number of buyers are getting involved in how these systems will be installed, or waiting until they occupy the house to better control the manner in which their system will be installed.
Most states recognize qualified credentialing organizations that certify radon measurement and mitigation professionals as well as analytical laboratories. Lists of these trained individuals can be found on the websites indicated below. In addition, your state may also have a listing on the state public health department website. Homeowners should also ask for references; require proof of certification, including agreement to follow protocols and codes of ethics; ask for proof of insurance including workers’ compensation; and ask for a clear contract with details of guarantee and warranty.