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What is Radon?

Radon is a colorless, odorless and tasteless radioactive gas occurring naturally in the soil.  It is produced from radium, a byproduct formed in the decay of uranium.   You cannot see, smell, or taste radon but it still may be a problem in your home. When you breathe air containing radon, you increase your risk of getting lung cancer.


Where does radon come from?

Radon levels in the soil vary due to soil chemistry.  Factors such as weather, soil porosity, soil moisture, and the air pressure within the house determine how much radon escapes from the soil.  Radon follows the path of least resistance to escape to the surface.  Air pressure inside your home is usually lower than pressure in the soil around your home foundation.  Because of this difference, your house acts like a vacuum, drawing radon in through foundation cracks and other openings.  Radon can even enter your home through well water.  Radon is found all over the U.S.  It can get into any type of building – homes, offices and schools – and can build up to hazardous levels.


What is the average level of radon found in homes in the U.S.?

Based on a national residential radon survey completed in 1992, the average indoor radon level is about 1.3 picocuries per liter (pCi/L) in air in the United States. The average outdoor level is about 0.4 pCi/L.  Nearly one out of every fifteen homes tested in the U.S. is estimated to have elevated radon levels (4 pCi/L or more).  There is only way to know whether your home has a radon problem – perform a radon test.


Why you should test for radon?

The Environmental Protection Agency (EPA) considers radon to be the second leading cause of lung cancer in the United States today.  Exposure to radon in the home is responsible for an estimated 20,000 lung cancer deaths each year.  If you smoke and your home has high radon levels, your risk of lung cancer is especially high.  The U.S. Surgeon General, the American Medical Association and the National Council of Radiation Protection recommend testing for all homes and buildings.  Radon can be present in homes with and without basements and in new homes as well as old homes.


What can we do for you?

The National Radon Safety Board (NRSB) recommends that you use a trained and qualified professional to test your home.  All of our inspectors are fully certified by NRSB for radon testing.  Our in-house lab gives us the ability to provide total quality control over the test results, and to offer results within one business day after the detectors have been retrieved.  Our radon results and reports are fully recognized in real estate transactions.  There are two general ways to test for radon:

Short-Term – Short-term testing encompasses a minimum time frame of 48 hours and includes any test length up to 90 days (short-term testing is your best choice if you need results quickly.)

Long-Term – Long term tests are conducted from 90 days up to one year.  Radon levels tend to vary from day to day and season to season, so a long-term test will reflect your year-round average radon level.

Post Remediation Testing – Retest three to four days after mitigation.  Retesting should occur every two to three years to confirm that radon levels are staying low.


How we test for radon

We use the E-PERM® System, a passive device used to measure radon concentrations in the air.  It consists of a charged Teflon disk or electret which is screwed into an open-faced ionization chamber to establish an electrostatic field.  When this happens a passive ionization chamber is formed.

Over time, radon gas diffuses passively into the chamber. The alpha particles emitted from the decay of radon ionize the air molecules.  The ions are attracted to the charged surface of the electret and over time neutralize and reduce the charge that was originally present.  The electret charge is measured before and after the exposure, and the rate of change is proportional to the concentration of radon in the area.

Electret ion chambers have no moving parts or electronic components and are unaffected by ambient environmental conditions.  The U.S. EPA has used this technology to establish the natural ambient radon levels in all states in the U.S.  According to the EPA (document EPA 402-F-93-003-I), more than 50% of all the radon detectors submitted for radon proficiency tests are E-PERMs, which also have the highest pass rate.


Radon Testing Procedures

If you schedule a radon test with your home inspection, the inspector will place two detectors in the lowest livable area of the home when he arrives for the inspection.  As per EPA guidelines, the detectors must remain in place for a minimum of 48 hours.  However, if desired, they can remain in place up to a maximum of ninety days for a short-term radon test.  A longer exposure does not imply that the readings will be higher;  if anything, a longer exposure adds to the objectivity of the test.

Once the detectors have been retrieved, the inspector will analyze the results using our in-house laboratory. These results are verbally available within one business day of retrieval, and are followed-up by a detailed report sent electronically to the client via email.


Procedures for Occupants

To ensure accurate readings for analysis, a responsible occupant of the house will be asked to maintain the conditions listed below during the test period.  Occupants should follow these procedures carefully or the test results may be deemed invalid:

  • Windows and doors must be kept closed at least 12 hours prior to our arrival and throughout the test period.  If doors and windows are found open when we arrive to place the detectors, testing cannot be performed.  Doors may be opened during the test for normal, momentary entering and exiting.  Windows must be kept closed because, when open, they can raise or lower radon levels.
  • Please do not touch, cover, move or alter the performance of any detectors or other controls that may be placed with the detectors for non-interference purposes.
  • Please do not operate any whole house fans. Do not use any fireplaces or wood stoves, unless they are a primary heat source, and keep all dampers closed if not in use.
  • You may operate the heating and air conditioning normally.  However, please turn off and keep off any equipment that supplies fresh air to the dwelling unless it is vented supply air to a combustion appliance.
  • The dryer, range hood, bathroom fan or attic ventilating fan can be operated.  This equipment should only be operated normally because any exhaust fan or any combustion appliance may increase the negative pressure in the dwelling, which can raise or lower any radon concentration.  
  • A signature will be requested to verify that these closed-house conditions have been explained to a responsible occupant of the house or their designated representative prior to testing, and that the conditions explained above were adhered to during the testing period.


What do your radon test results mean?

The concentration of radon in the home is measured in picocuries per liter of air (pCi/L).  If your radon level is below 4.0 pCi/L , you do not need to take action.  However, radon levels less than 4.0 pCi/L still pose some risk and in many cases may be reduced.  If the radon level in your home is between 2.0 and 4.0 pCi/L, the EPA recommends that you consider fixing your home.  The national average indoor radon level is about 1.3 pCi/L.  The higher a home's radon levels, the greater the health risk to you and your family.  Smokers and former smokers are at especially high risk.  There are straightforward ways to fix a home's radon problem that are not too costly.  Even homes with very high levels can be reduced to below 4.0 pCi/L.

Radon is the second leading cause of lung cancer, after smoking.  The U.S. Environmental Protection Agency (EPA) and the Surgeon General strongly recommend taking further action when the home's radon test results are 4.0 pCi/L or greater.  

If your radon level is 4.0 pCi/L or greater, use the following charts to determine what your test results mean.  Depending upon the type of test(s) you took, you will have to either test again or fix the home.  NOTE: All tests used by the Building Inspector of America meet EPA technical protocols.


CHART 1: Radon Test Conducted Outside Real Estate Transaction

Type of Test(s)

If Radon Level is 4.0 pCi/L or Greater

Single Short-Term Test

Test Again *

Average of Short-Term Tests

Fix The Home

One Long-Term Test

Fix The Home

* If your first short-term test is several times greater than 4.0 pCi/L – for example, about 10.0 pCi/L or higher – you should take a second short-term test immediately.


CHART 2:  Radon Tests Conducted During Real Estate Transaction (Buying or Selling a Home)

Type of Test(s)

If Radon Level is 4.0 pCi/L or Greater

Single Active Short-Term Test
(this test requires a machine)

Fix The Home

Average of 2 Passive Short-Term Tests*
(these tests do not require machines)

Fix The Home

One Long-Term Test

Fix The Home

* Use two passive short-term tests and average the results.