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Karst Areas - Real Estate Transaction Testing

If you choose to base your real estate transaction decisions on a short-term test in karst areas, follow-up with a 12-month confirmatory test immediately (or soon after you move into the home).

Testing Recommendations For Real Estate Transaction Testing

Where To Test

  • Test in the lowest level of the home suitable for occupancy. This means the lowest level that can be used as living space which is finished or does not require renovations prior to use. (If you decide to finish or renovate an unfinished area of the home in the future, a radon test should be done before starting the project and after the project is finished.)
  • Do not:
    - test in the bathroom, kitchen, laundry room, crawl space, sumps, cupboards, nooks, or closets.
    - place test vial in direct sunlight or near excessive heat sources, such as appliances or fireplaces.
    - place test vial near drafts, and do not operate ceiling fans in the room being tested.

How To Test

  • Observe closed-house conditions: close windows and outside doors for at least 12 hours before beginning the test.
  • Do not test during severe storms or periods of high winds.
  • Test for no less than 48 hours and no more than 96 hours.
  • Fill out the data form for the exact start and end time and date of the test.
  • Place the test vial at least:
    - 20 inches above the floor
    - 3 feet from exterior windows or doors
    - 1 foot from an external wall that has no openings
    - 4 inches from other objects
  • If you need results quickly, request expedited service with the lab handling the test device.

Three Ways To Take a Short-Term Test For Real Estate Transactions

1. Simultaneously take two short-term tests at the same time, in the same location (4-inches apart) for at least 48 hours. Fix the home if the average of the two tests is 4 pCi/l* or higher.

2. Sequentially take an initial short-term test for AT LEAST 48 hours. Immediately upon completing the first test, follow with a second test using an identical test device in the SAME LOCATION as the first test. Fix the home if the average of the two tests is 4 pCi/l* or higher.

3. Hire a certified radon tester to test the home with a continuous monitor for at least 48 hours. Fix the home if the average radon level is 4 pCi/l* or higher.

For information on ordering radon testing kits, please contact us at 1-800-582-1866.

*The EPA recommends reducing radon levels that are 4 pCi/l or higher. One measurement used to determine radon levels is picocuries per liter of air. The higher the radon level in your home, the sooner you should take action to reduce your exposure. Radon levels in most homes can be reduced below 4 pCi/l with mitigation.

Page last updated: May 13, 2021