Radon Testing Frequency: When and Why to Retest
Testing is the only way to understand your home's radon levels and whether you need to take action. Many homeowners test once and assume they’re covered forever, or only think about radon during a real estate transaction. The truth is that radon testing isn’t a one-and-done situation. Levels can shift over time, especially when you make changes to your home or its foundation.
In this guide, we cover how often you should test for radon, when retesting is essential, and why consistent monitoring and professional radon mitigation systems are key to long-term protection against radon exposure.
When to Test for Radon Initially
You should first test for radon when you move into a home, ideally during the home-buying process or shortly after moving in. Every home should be tested for radon, regardless of age or location. Radon levels can vary dramatically from house to house, so you can’t assume your home is fine just because your next-door neighbor’s test came back low.
If you’ve never tested your home for radon, now is the time. You can pick up an EPA-approved radon test kit at a hardware store, order one through the National Radon Program, or hire a certified professional to perform the test for you. Whichever route you choose, the goal is to determine if you're above or below the EPA’s action level of 4.0 pCi/L.
How Often Should You Test for Radon?
You should test your home for radon every two years, even if your initial levels were low. Homes settle and foundations shift over time, creating new cracks and pathways for radon gas to enter. A test that came back clean three years ago may no longer reflect what’s happening in your home today.
The two-year radon testing frequency is just as important if you already have a radon mitigation system installed. Regular retesting confirms your system is still doing its job and alerts you to any maintenance issues, such as a failing fan or a blocked vent, before they put your family at risk.
Situations That Call for Retesting Radon Levels
While testing every two years is a solid rule of thumb, certain scenarios call for retesting sooner. You should retest radon levels in the following situations.
After Mitigation System Installation
Radon mitigation systems are designed to vent radon from beneath your house up and out above your roofline, lowering high radon levels inside your home. However, you’ll want to confirm your new system actually works.
Wait at least 24 hours after installation for the system to begin doing its job, then run a short-term test to verify your radon levels have dropped well below the EPA’s 4.0 pCi/L action threshold.
After Major Home Renovations
Home renovations can create new pathways for radon to enter your home, especially projects that involve the basement or the lowest level of the house. Basement finishing, adding a new room, installing new flooring over a slab, or modifying ductwork can all change how air moves through your home and how easily radon migrates inside.
Plan to retest within a few months of completing any major renovation.
After Foundation Repairs
Radon works its way into your home from the soil beneath the foundation. If you repair, replace, or modify the foundation in any way (including sealing cracks, installing a new sump pump, or excavating around the home), you may inadvertently create new paths for radon to enter.
Retest as soon as the work is complete and your home has returned to normal living conditions.
Before Selling Your Home
Is radon testing mandatory in real estate transactions? In most states, no, but it’s a smart way to create peace of mind for both you and the buyer. If you’re selling, recent test results give prospective buyers confidence in the home’s safety.
Don’t Want to Forget to Test? Get a Radon Monitor
Life gets busy, and remembering to retest for radon every two years isn’t always realistic. If you want an easy way to stay informed about changes in your home’s radon level, consider investing in a continuous radon monitor. These devices track the radon levels in your home over time and display daily, weekly, and long-term averages, so you don’t have to worry about a single short-term test catching an unusual day or normal fluctuations.
We’ve put together a list of radon monitors we trust so you can pick a reliable model today without sifting through dozens of websites and reviews.
Protect Your Home for the Long Term
Testing is an important first step, but if your results are elevated, mitigation is the next critical step. The Radon Guys provide professional radon mitigation systems that reduce levels effectively for the long term. If your recent radon test shows levels above the recommended limits, don’t wait. Contact us to install a dependable mitigation solution that protects your home and family.
