When Should You Test for Radon?
By Daniel SmokeDirector of Operations
The EPA and the Surgeon General recommend that all homes below the third floor be tested for radon. Radon levels vary significantly between neighboring properties, so your neighbor's results tell you nothing about your own. Testing is inexpensive, straightforward, and provides the only reliable answer about whether your home has an elevated radon risk.
When Buying a Home
A radon test is one of the most valuable inspections a homebuyer can request. Radon testing during the home inspection period gives you options.
You can negotiate remediation with the seller, walk away if results are unacceptable, or factor mitigation cost into your offer. If the seller provides prior test results, consider whether the test was recent (within two years) and long-term (90 days or more).
Also consider whether it was conducted with proper protocols and representative of the lowest livable level of the home. A professional test conducted specifically for the transaction is more reliable than informal prior results.
After Moving Into a Home
If you have moved into a home that has not been tested, testing should be a near-term priority. The same is true if the last test was more than two years ago. This is especially important if you spend significant time in lower levels of the home, including basements and ground-floor rooms. The EPA recommends testing any home you haven't tested, regardless of age, construction type, or location.
After Renovation or Construction Changes
Renovation can change the radon dynamics of a building. Adding a basement, finishing a previously unfinished lower level, changing the HVAC system, adding sub-slab drainage, or significantly sealing the building envelope can all alter radon entry points and ventilation patterns. If you have completed significant renovation work on the lower levels of your home, a follow-up test is warranted even if you tested previously.
If Your Mitigation System Has Been in Place for Years
Mitigation systems require periodic testing to confirm they are still working effectively. Fans can degrade, pipes can become blocked, and the pressure differential can change as the building ages. The EPA recommends testing every two years after a mitigation system is installed. If levels have risen above 4 pCi/L, the system may need service.
For Ongoing Peace of Mind
Long-term continuous radon monitors are increasingly available for homeowners who want ongoing visibility into radon levels. These devices provide rolling average readings and can alert you to sudden increases. They are a complement to, not a replacement for, periodic professional testing. This is especially true if you need documentation for a real estate transaction or regulatory requirement. At minimum, the EPA recommends testing every two years as a routine precaution.
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