Frequently Asked Questions
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Fortunately, there are other extremely effective means of keeping radon out of your home. 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 be mitigated to an acceptable level. Mitigation usually costs $1500. However, the cost may be higher in some states due to soil conditions.[/vc_column_text][/vc_accordion_tab][vc_accordion_tab title=”3. WHAT ABOUT RADON IN WELL WATER?”][vc_column_text]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. The average Colorado well tests about 3,000 pCi/L with one well testing more than 3,000,000 pCi/L.
Some peoples immune system is better than others. Because of these inherent differences, radon doesn’t affect everyone the same.
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
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.
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.
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, we 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. LET THE BUYER BEWARE. 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.
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.
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.
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.
Dig the suction pit under the floor as large as possible, or make sure it intersects the void beneath a grade-beam foundation.
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.
Caulk the large cracks and joints in the concrete floor slab to prevent unnecessary heat loss.
Install a manometer or warning device to alert you if anything goes wrong with the system.
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.
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