The Okanagan is a known radon hotspot in BC. Here's what radon is, why it matters here specifically, how to test, and what to do if your levels are high — for buyers, sellers, and current homeowners.
Radon is a naturally occurring radioactive gas produced by the breakdown of uranium in soil and rock. It's invisible, odourless, and tasteless — there is no way to know if it's present in your home without testing.
Radon is the leading cause of lung cancer in non-smokers, and the second leading cause overall after smoking. Health Canada estimates radon contributes to roughly 16% of lung cancer deaths nationally — more than 3,000 Canadians annually. The risk comes from long-term exposure, not a single event: the longer you breathe elevated radon levels, the higher your cumulative risk.
Radon moves freely through soil and is released into outdoor air, where it dilutes to harmless concentrations. The problem is indoors: radon seeps into homes through foundation cracks, sump pits, drains, and construction joints — anywhere the building contacts the ground. Once inside, especially in a sealed-up, well-insulated home (exactly the kind people build for energy efficiency), it can accumulate to concerning levels. Basements and ground floors typically have the highest concentrations, since they're closest to the source.
This isn't a defect specific to certain "bad" properties — every home in Canada has some level of radon, because uranium exists in soil everywhere. The question is how much, and the only way to know is to test. Radon levels can vary significantly even between neighbouring homes, due to differences in foundation type, soil composition directly beneath the home, and ventilation.
This isn't a generic disclaimer — the Okanagan Valley specifically has elevated radon risk due to its underlying geology, and health authorities have flagged it directly.
The granite bedrock and glacial till common throughout the Okanagan Valley contain trace amounts of uranium. As it decays underground, it releases radon gas into the soil — which can then migrate into homes built on top of it. The BC Interior generally, and the Okanagan specifically, is recognized by Health Canada and the BC Centre for Disease Control as a higher-radon-potential region compared to BC's coastal areas.
In September 2025, the Regional District of Okanagan-Similkameen (which includes Osoyoos, Oliver, Penticton, Summerland, and Keremeos) voted to join the federal radon testing program — a direct acknowledgment of the region's risk profile and a sign that radon awareness is becoming a more prominent local issue. Communities throughout the wider Okanagan, including Keremeos specifically, have previously participated in free radon test kit initiatives.
If you're buying, selling, or already own a home in the South Okanagan, radon testing deserves the same routine attention as any other home health and safety check. It's not about being alarmed — it's about being informed. Most homes with elevated radon can be brought below the guideline relatively affordably once identified.
Health Canada recommends a minimum 3-month test, ideally during the fall/winter "heating season" when homes are sealed up and radon tends to accumulate most. Radon levels fluctuate significantly day to day and season to season — a quick test over a few days can give a misleading picture. The Canadian Radon Guideline is based on the average annual concentration, which is why long-term testing is the standard recommendation.
Short-term tests (a few days to a week) are sometimes used for time-sensitive situations like a real estate transaction, but research has shown they can be less reliable than long-term testing for predicting annual averages. If a short-term test is used, it's worth following up with a long-term test after possession for a more accurate picture — and treating a high short-term result as a reason for caution, not necessarily a definitive answer.
Test kits are placed in the lowest lived-in level of the home (a finished basement counts; an unfinished crawlspace doesn't) — away from drafts, exterior walls, windows, and direct heat sources. The device needs to remain undisturbed for the full testing period for accurate results.
Test kits can be purchased through the BC Lung Foundation and various online retailers. Free loaner electronic monitors are available through BC Lung's Radon Detector Library Lending Program, accessible through Okanagan, Kootenay, and Thompson-Nicola regional library networks — borrowable for up to 4 weeks at no cost. Given the RDOS's recent move to join the federal testing program, watch for local testing initiatives and potential free kit programs through the regional district as well.
Health Canada's Canadian Radon Guideline recommends corrective action if the average annual radon level exceeds 200 becquerels per cubic metre (200 Bq/m³). Importantly: there is no level considered completely risk-free. The higher the level, the sooner action is recommended — but even homes below 200 Bq/m³ can benefit from improvement, since lower is always better for long-term health.
The standard solution is a sub-slab (or sub-membrane) depressurization system — a pipe and fan system that draws radon gas from beneath the foundation and vents it safely above the roofline, before it can enter the living space. This is typically installed by a certified C-NRPP (Canadian National Radon Proficiency Program) professional. Systems can be passive (relying on natural pressure differences) or active (using a continuously running fan) — active systems are more effective and most commonly used when levels are significantly elevated.
A typical active sub-slab depressurization system installed by a certified professional runs roughly $1,500–$3,500 in most of Canada, depending on the home's foundation type and complexity. This is a one-time installation cost with minimal ongoing expense (the fan uses a small amount of electricity, similar to a light bulb running continuously). After installation, a follow-up test confirms the system brought levels below the guideline.
New homes built to current BC Building Code typically include a "rough-in" for a future radon mitigation system — a capped pipe beneath the foundation that can be activated with a fan if testing later reveals elevated levels. This makes future mitigation simpler and cheaper. Even new homes with a rough-in should still be tested after move-in — a rough-in is a precaution, not a guarantee.
Radon is one of the more manageable home health risks once identified — testing is inexpensive (or free), and mitigation is a well-established, relatively affordable, one-time fix. The risk lies entirely in not knowing. A property with elevated radon and a properly installed mitigation system is not a property to avoid — it's a property where the problem has already been solved.
As covered in our What to Expect During an Inspection Guide, a standard BC home inspection does not include radon testing by default — it must be arranged separately, either through your inspector (many now offer it as an add-on) or a dedicated radon testing service.
Since accurate testing ideally takes 3 months, a typical 7-14 day subject period doesn't allow for a full long-term test. Practical options: ask the seller for any existing test results and dates, arrange a short-term test as a preliminary indicator during your subject period, or proceed with the purchase and complete a long-term test after possession (mitigation can be installed after the fact if needed — it's not typically a transaction-ending issue).
Given how well-known the Okanagan's radon profile is becoming, it's reasonable to ask sellers whether the home has been tested and, if so, what the results were. Some South Okanagan sellers — particularly those who've owned their home for years — may already have test history, especially given increasing regional awareness.
BC's Property Disclosure Statement doesn't currently ask a specific radon question on most versions, but if you've tested and know your home has elevated levels, that's the kind of known, material information that's safer to disclose than to withhold — consistent with the disclosure principles covered in our Seller's Guide. If you've never tested, you have no obligation to test before selling, and "unknown" is a legitimate, honest answer if asked.
Given increasing buyer awareness of radon in the Okanagan specifically, having a recent test result (and a mitigation system already in place, if needed) can be a genuine selling point — it answers a question more buyers are starting to ask, and it removes a potential point of post-purchase friction. A long-term test takes 3 months, so this needs to be planned ahead of a listing date, not done last-minute.
Document it. Keep records of when it was installed, by whom (ideally C-NRPP certified), and any post-installation test results showing levels below the guideline. This documentation reassures buyers and their inspectors, and avoids the system being flagged as an unexplained, unusual feature during inspection.
Whether you're buying, selling, or just want to understand a South Okanagan property's radon profile, Pat can point you toward testing resources and certified mitigation professionals in the area.