Radon Testing

Testing your home for radon is both easy and relatively inexpensive. Testing can be done with a do-it-yourself kit that you send back to a laboratory for analysis, or you can hire a professional to test for you. If you are willing to read and follow instructions, a do-it-yourself kit may be adequate. However, if you're involved in a real estate transaction, you may wish to hire a professional tester, as you will probably receive the results much faster. There are two main categories of radon tests: short-term tests and long-term tests.

Short-Term Radon Testing

Short-term tests are used as a screening device to see if a home may have a radon problem. The tests generally run from 3 to 7 days, and must be conducted under "closed house conditions," where all doors and windows are kept closed except for normal entry and exit, and where exhaust fans and window air conditioning units are not being used. The most common and most readily available short-term test is an activated carbon (charcoal) device. This device may be a plastic or metal canister, a glass or plastic vial, or a paper pouch or envelope. Charcoal test kits can be purchased from most local hardware or home improvement stores.

Short-Term Radon Test Kit

In addition, test devices called continuous radon monitors (CRMs) are available for short-term testing. These are electronic devices that require a power source such as an electrical outlet or internal battery, and a trained operator. CRMs are frequently used for measurements conducted in conjunction with a real estate transaction. The price of a CRM measurement typically ranges from $75 to $200. Find out where you can get a short-term radon test kit.

Short-Term Radon Test Video

Long-Term Radon Testing

Long-term tests generally involve a device called an alpha track detector. This small plastic canister can be used for time periods ranging from 90 days to one year. It is a passive monitor (requires no power source), and is most often used as a year-long follow-up measurement when a borderline-high radon level has been found during a short-term test. The one-year measurement provides an estimate of your average annual exposure, giving you a better idea of what you are actually exposed to on a long-term basis. 

It allows you to measure the radon level under normal living conditions over a relatively long period of time, and as such, takes into account all the changes in weather that occur throughout the year, as well as the changes in the way you occupy/use your house under different weather conditions. Weather conditions and ventilation habits can influence the radon level in your house, and with this test you measure the way you actually live, opening and closing doors and windows any time you want, and using mechanical ventilation (furnace, air conditioner, exhaust fans, whole house fans, etc.) as you wish. To order long-term radon kits online, visit AirChek or Accustar Labs. Washtenaw County no longer offers long-term radon test kits for sale.

Long-Term RadonTest Kit

Testing Recommendations

Follow these recommendations when testing your home for radon.

Step 1: Take a Short-Term Test

  • Test the lowest livable level of your home, such as a finished basement (or an unfinished basement that could easily be finished or that you plan on finishing). If you do not have a basement, test on the main floor of the house. You don't need to test crawl spaces or "Michigan basements" unless people spend a lot of time down there!
  • If your home has multiple foundations, test each area with a different foundation. For example, if the main part of your home is above a finished basement, and a family room is on a cement slab, a radon test should be conducted in the basement as well as in the family room.
  • If your short-term test result is less than 4.0 picocuries per liter (pCi/L), your home has radon levels lower than the Environmental Protection Agency's (EPA) recommended action level. Although exposures in this range do present some risk of lung cancer, reducing levels this low may be difficult, and sometimes impossible. Consider testing again in the winter to verify the results. Also, retest if you put an addition on your home, if you install a new heating or cooling system, or if you change your living patterns and begin occupying a lower level of your home (such as creating an exercise or play room in the basement).
  • If your short-term test result is 4.0 pCi/L or higher, take a follow-up test to be sure.

Step 2: Follow Up on Your Test Results

  • If you need results quickly (generally if your first test was 8.0 pCi/L or higher), take a second short-term test. Test the same rooms using the same procedures. See Step 3.
  • For a better understanding of your year-round radon level (generally if your first test was 4.0 to 8.0 pCi/L), take a long-term test. This time, test all livable levels of your home, such as the basement, first floor, and second floor.

Step 3: Fix Your Home if Necessary

  • If you followed up with a long-term test, fix your home if the result is 4.0 pCi/L or higher.
  • If you followed up with a second short-term test, the higher your results, the more certain you can be that you should fix your home. Fix your home if the average of your first and second test is 4.0 pCi/L or higher.