By Jason Hafso, REALTOR® | MaxWell Challenge Realty · Reviewed September 30, 2026
Imagine two similar houses on the same Spruce Grove street. Both have finished basements. Both look well maintained. One has a low radon test result; the other has an elevated one. You couldn't pick which was which from a showing, a listing photo or the year they were built.
That is what makes radon an unusual home issue. You can't see, smell or taste it, and the clues we normally use to judge a house aren't very useful. The good news is that a simple test can give you an answer—and an elevated result can usually be addressed.
What is radon, and why are we hearing more about it?
Radon is a naturally occurring gas released from soil and rock. Outdoors, it disperses. Indoors, it can make its way through openings where a house meets the ground and accumulate in the air we breathe. Prolonged exposure increases the risk of lung cancer, especially for people who smoke. It isn't a gas that makes you suddenly sick after one afternoon in the basement; the concern is what you breathe over many years. The World Health Organization explains the health evidence.
Much of the early research came from miners. Since then, studies of ordinary homes have shown that residential exposure matters too. Canada lowered its radon guideline in 2007, and a much larger cross-Canada survey reported in 2024 found elevated levels in more homes than an older survey had suggested. That doesn't mean every Canadian house suddenly became more radioactive. It means we have a fuller picture than we once did.
The research gives us a reason to take radon seriously. It doesn't give us a reason to panic over a single reading.
The surprising part: your house has to answer for itself
Parts of the Prairies, Atlantic Canada, the North and B.C.'s Interior have higher proportions of homes with elevated radon. The 2024 survey estimated that roughly one in six homes in the Edmonton metropolitan area exceeded Canada's guideline. That is an Edmonton-area estimate, not a measured rate for Spruce Grove or for any particular neighbourhood. See the survey's regional findings.
A map can tell us where testing is especially important, but it can't tell us what is happening in your basement. Soil conditions, the foundation, ventilation and air pressure all play a part. Even neighbours can get very different results.
Nor can you rule radon out because a home is new. More airtight construction can affect how gases accumulate, while modern radon-control features may help manage them. Neither factor predicts a specific home's result. Alberta's 2014 Building Code, in force from May 2015, introduced radon rough-in requirements for applicable new houses. A capped pipe is preparation for possible mitigation; it isn't a working fan or proof that anyone tested the air. The code that applied to a particular house depends on its permit and construction circumstances. Alberta's code history and Health Canada's measurement guide explain those distinctions.
How to get an answer you can trust
The most useful result is a long-term average, not the number on a screen this morning. Radon changes with the weather, the season and the way a house is used. A digital monitor can show those ups and downs; a passive detector sent to a lab is another straightforward choice. Whichever you use, follow the instructions and run the test for at least three months during the heating season. Health Canada gives more precise timing and placement guidance in its home testing guide and its guide to electronic monitors and long-term detectors.
Place the detector on the lowest level people regularly use. That might be a basement bedroom or family room. If the basement is just storage, the main floor may be the appropriate place. A furnace room or a spot by an open window won't give you the answer you want.
If a monitor shows a high number one day, let the test run. A short spike is information, but it isn't the long-term result on which to make a decision. Likewise, opening a window may change today's reading without solving a persistent problem.
What if the result is high?
Canada's guideline is 200 Bq/m³ as a long-term average. Those letters are simply the Canadian unit used on a radon report. Above that level, Health Canada recommends corrective action within one year. The number is a practical action point, not a sharp boundary between safe and unsafe air: a result just below it does not mean zero risk. The U.S. uses a somewhat lower action level, but both countries recognize the same gradual, long-term risk.
The usual fix is a system that draws soil gas from beneath the house and vents it outdoors with a fan. It can substantially reduce indoor radon. Have a qualified professional assess the home, then test again to confirm the result. Health Canada's reduction guide explains the options and follow-up testing. A high result doesn't, by itself, mean the foundation is defective or the house is unsellable.
What does this mean if you're buying or selling?
This is where the timing gets awkward. A typical purchase condition lasts days; a meaningful radon test takes months. As a REALTOR®, I can't determine a home's radon level by walking through it, spotting a rough-in or reading a nearby home's result. A home inspection doesn't measure the long-term average either.
If a seller has a test report, ask when and where the test was done, how long it ran, and whether any mitigation was followed by another test. Sellers who want to know before listing can test well ahead of time. Buyers without a reliable long-term report can plan to test after possession, ideally during the heating season. A short test during a transaction may offer preliminary information, but it can't settle the long-term question. Health Canada has guidance specifically for real estate transactions.
If you've tested before, consider another test after major changes to the basement, ventilation or energy efficiency, or if you move into a newly built home with only a rough-in. A past result is useful history; it doesn't guarantee today's level.
Radon is one of the few things about a home that no amount of careful looking will reveal. The sensible response is neither to dismiss it nor to fear every basement. Test the home you actually live in, use the long-term result, and deal with a high level if you find one.

