Radon is one of those things most people don't think about until someone mentions it, and then suddenly it's all they can think about. For years, the line on PEI was that radon wasn't really our problem. Newer data says otherwise: roughly 1 in 5 homes tested on the Island came in above the Canadian guideline. The good news is that testing here is easy and can be free, and a high result can be mitigated. [If you're still in the early stages of planning a move, Relocating to PEI: Everything You Need to Know About Buying a Home Here is a good place to start.]
What radon actually is.
Radon is a radioactive gas that comes up naturally out of the ground. You can't see it, smell it, or taste it. It gets into homes through cracks in the foundation, gaps around pipes, sump pits, and anywhere else the house touches soil. Concrete is porous, too, so some gas can move through the foundation itself. Outside, it disperses and isn't a concern. Inside, it can build up. In Canada, we often have little air movement out of the house (once we get it warm inside, we want to keep that heat in). This is why we see more radon build up from late fall through to spring: houses are sealed up and the air that is inside stays there. That matters, because long-term exposure to high levels is the second leading cause of lung cancer in Canada after smoking.
Wait, I thought PEI didn't have a radon problem?
You're not alone. Our red sandstone was long thought to produce less radon than the granite found elsewhere, and Health Canada's 2012 survey backed that up, finding only about 3.5% of PEI homes above the guideline. But the 2024 Cross-Canada Radon Survey, which used far more long-term home tests, found about 1 in 5 PEI homes at or above the guideline. Atlantic Canada as a whole now sits among the higher-radon regions in the country, with about 1 in 3 homes at or above the guideline. A smaller 2023 community project in Queens County, where 69 homes ran 91-day tests, found 14% above the guideline. The exact number depends on the study, but the takeaway is the same: radon on PEI is more common than most of us were told.
What counts as "high."
The Canadian guideline is 200 Bq/m³ (becquerels per cubic metre, which you will never need to say out loud). If your home tests above that guideline, then it is recommended that radon mitigation steps be taken, within a year to 2 is the standard timeline.
How to test (and how to do it for free).
When it comes to testing, there are several options ranging in price from free to $300. You can borrow a short-term radon detector for free from PEI public libraries with a library card, through a program run by the Lung Association of Nova Scotia and PEI. If you'd rather own a long-term test, the Canadian Lung Association sells a long-term alpha track radon test for $44.95. If you'd like ongoing readings instead of a one-time result, they also sell a digital radon monitor for $179 that keeps tracking your levels over time. A long-term test is the gold standard. Health Canada recommends testing for at least three months (91 days is the magic number), in the lowest level of the home where someone spends at least four hours a day, during the colder months when the windows are shut. In other words: right now is the perfect time to start one. If you need an answer faster, you can have a quick test done that measures levels over about four days, and it currently runs around $300. If you want more information on the four-day test, reach out to me and I'll point you in the right direction. It's a useful snapshot, but radon levels swing day to day and season to season, so a long-term test is what tells you your real average. [If you're working through your fall to-do list anyway, PEI in the Fall: A Locals' Guide to What Changes has the rest of it.]
If your number comes back high, it can be mitigated. A high reading sounds scary, but it isn't a "the house is ruined" situation. The most common solution is a system that pulls air from under the basement slab and vents it outside, and it's very effective. Additionally, sealing any cracks in the foundation and ensuring that you have a working air exchange system are both steps that can be taken to mitigate radon gas collecting. Look for a mitigation contractor certified through the Canadian National Radon Proficiency Program (C-NRPP), then retest afterward to make sure it's working. Keep in mind that mitigation won't guarantee there will never be radon in the house. The goal is to bring the level down to within the guideline, which is why retesting matters. As for cost, current local estimates put mitigation on PEI somewhere between $1,000 and $4,000, depending on the house.
Moving to PEI? Here Are the Radon Questions I'd Expect You to Have
"Is radon worse on PEI than where I'm coming from?" It depends where you're coming from. In the 2024 Cross-Canada Radon Survey, PEI's rate (about 1 in 5) is close to the national average (17.8%). It's lower than Nova Scotia (more than 1 in 3) and New Brunswick (about 1 in 4), and higher than Toronto (about 1 in 22) or the Vancouver area (about 1 in 113). So if you're coming from coastal BC or the GTA, radon may be a newer thing to think about. Either way, the provincial number is a reason to test, not a prediction for any one house.
"Will my home inspection check for radon?" Usually not. A standard home inspection looks at the structure and systems of the house, and radon testing typically isn't part of it. That said, some home inspectors on the Island do offer a radon test as an add-on, so it's worth asking when you book your inspection.
"Can I test before I buy?" You can, but not with the gold-standard test. A 91-day test won't fit inside a typical condition period, so the realistic option during a purchase is the quick four-day test mentioned above. It gives you a snapshot rather than a long-term average, so read it as a "probably fine" or "worth a closer look," not a final verdict. To date, I have yet to see an Agreement of Purchase and Sale address radon in the conditions, but I do have a plan as to how I would do it if it is an issue you would like to address. If radon's on your list, tell me early and we'll build it into your offer.
"I'm buying a brand new build. Doesn't that mean no radon?" Not necessarily. Since March 31, 2021, every new single-family and semi-detached home on PEI has had to be built to the National Building Code. Before that, only Charlottetown, Summerside, and Stratford used it. The code requires a soil gas barrier under the basement slab and a radon rough-in: a capped, labelled pipe through the basement floor that makes it much easier (and cheaper) to add a radon system later if you need one. But a rough-in doesn't do anything on its own. It's just a capped pipe until someone hooks a fan up to it. And if you're looking at a home built outside those three municipalities before 2021, it may not have one at all. New build or not, it's still worth testing. "Can I test before I actually move?" Not really. You need to be living in the home through the heating season for a long-term test to mean anything, and the library detectors are for Island library cardholders. If you're still deciding where to land and want a rough feel from afar, Airthings (a company that makes digital radon monitors) publishes a map of indoor radon levels across PEI and a ranking of PEI towns by average indoor radon. Both are based on readings from people who own Airthings monitors, not a scientific survey, and some towns only have a handful of them, so treat it as a curiosity, not a reason to pick or skip a community. My advice: put it on your list for your first fall or winter here, alongside snow tires and finding a plow guy.
"If the house I love tests high, should I walk away?" This is a choice you have to make. It's the same as if something major came back on the home inspection. Only you can make the choice of whether it is something you can live with or not. Radon can be mitigated, so it's a cost to weigh, but not necessarily a dead end.
Radon isn't something to lose sleep over, but on PEI it's definitely something to check off. Borrow a detector, set it in the basement this winter, and you'll have your answer by spring.
Got more questions about what island life is actually like? Your Questions Answered: Moving to Prince Edward Island rounds up the ones I get asked most.