Short answer
Test every home at least once, then again when something changes: after a radon fix and at least every two years after that, after major renovations, and when you start living on a lower level. After a low result, you may want to test again sometime in the future.
Next step: check the rules where you rent or let. Radon rules for rentals by state
How often should you get your house tested for radon? There is no fixed yearly schedule for a home without a radon system. Retest on a lower floor if you start living there, before and after a renovation, and when you buy or sell, since a buyer may ask for a new test if the last one is more than about two years old.
A home with a
What to do next: if the home has never been tested, start with a
At a glance · 1 min read
There is no fixed yearly schedule for a home without a radon system. Test once to find out where you stand, then test again when something changes: the house, the way you use it, or its owner. A home with a
| Situation | When to test |
|---|---|
| Never tested, or the level is unknown | Now |
| After a radon fix | Within 30 days of installation, then at least every two years |
| Before and after renovating | Before the work starts and again after it is finished |
| You start using a lower floor | Retest on that level, for example after turning a basement into a bedroom or office |
| After heating, ventilation or air-conditioning changes | Retest; such changes might affect radon levels |
| Buying or selling | Test during the sale; a buyer may ask for a new test if the last one is more than about two years old |
| A new home | As soon as possible after you move in, even if it was built radon-resistant |
| Your result was low | You may want to test again sometime in the future |
In a picture · 1 min read
Radon levels vary from day to day and season to season, and even from hour to hour within one building. A single
1Step 1: Take a short-term test.
2Step 2: Follow up with either a long-term test or a second short-term test.
3Step 3: Decide whether to fix your home.
So the first test answers today's question, and a high short-term result is followed by a second test before a decision. A
In a picture · 1 min read
A radon system changes the schedule. Test once after installation to confirm it worked, ideally by an independent tester, and then at least every two years to make sure the level stays low. In between, the system's warning device, usually a manometer, tells you whether the fan is working; if it shows a problem, call a contractor.
Day of installation
The system goes in
Keep the fan running at all times: it must run continuously for the system to work correctly.
No sooner than 24 hours
Earliest post-mitigation test
Test no sooner than 24 hours after your system is in operation with the fan on, if it has one.
Within 30 days
Post-mitigation test done
A two- to seven-day measurement is recommended, and EPA recommends an independent follow-up radon measurement as well as any test the contractor runs.
At least every two years
Retest
Retest your home at least every two years to be sure radon levels remain low.
Test conditions: Windows and doors must be closed 12 hours before and during the test, except for normal entry and exit. Not drawn to scale.
After a remodel. After you remodel, retest in the lowest lived-in area to make sure the construction did not reduce the effectiveness of the radon reduction system.
A remodel also calls for a retest: after major changes, test the lowest lived-in area to make sure the work did not reduce the system's effectiveness. More on the first check is in how long after radon mitigation can you retest.
At a glance · 1 min read
A sale is its own trigger. Sellers do best to test early and keep the results; buyers often want a recent test, by someone not involved in the sale, in the lowest level they might use.
| Reason | Why it matters |
|---|---|
| The last test is not recent, for example more than two years old | Levels and the house may have changed since |
| The home was renovated or altered after the test | Renovations can change radon levels |
| The buyer will live on a lower level than was tested | Lower levels, near the ground, often have more radon |
| The testing checklist was not followed | An improperly run test may be inaccurate |
The full picture for buyers and sellers is in the buying a house with radon guide.
Questions · 1 min read
Not necessarily. Without a radon system there is no set yearly schedule: test again when the house or the way you use it changes. With a system, retest at least every two years.
Not on a schedule, but you may want to test again sometime in the future, and you should retest if you start living on a lower level or renovate.
At least every two years after the first post-installation test, and again after any remodel.
It is a good idea: changes to heating, ventilation and air conditioning might affect radon levels, and a buyer may ask what changed since the last test.
Yes. Every new home should be tested as soon as possible after occupancy, even one built with radon-resistant features.
Levels vary by season, so a single short-term test cannot show the whole year. A long-term test, more than 90 days, is the better measure of the year-round average.
Living with a home over the years: retests, a system to look after, and new builds.
Living with a radon mitigation system, from the manometer to maintenance and retesting.
Read the guideHow radon-resistant construction works, whether it is enough, and how to make it active.
Read the guideWhy a new home still needs a radon test, when to test after move-in, and what to do if the result is elevated.
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