What radon level triggers Calgary mitigation?

Health Canada's action level for radon is 200 Becquerels per cubic metre (200 Bq/m³) — at or above this level, mitigation is strongly recommended regardless of where you live in Canada, including Calgary.

Radon is a serious concern in Calgary and across Alberta. The province sits on uranium-rich geology, and Calgary's expansive clay soils and rocky substrates can channel radon gas directly into homes through foundation cracks, sump pits, floor drains, and utility penetrations. Alberta consistently has some of the highest radon readings in Canada — Health Canada's national surveys found that roughly 1 in 5 Alberta homes exceeds the 200 Bq/m³ action level, which is significantly higher than the national average of about 1 in 14 homes.

Understanding the Numbers

The scale matters here. At 100–200 Bq/m³, Health Canada recommends mitigation within 2 years. At 200–600 Bq/m³, mitigation should happen within 1 year. Above 600 Bq/m³, you should act within a few months — this is a serious health risk. For context, radon is the leading cause of lung cancer in non-smokers in Canada, responsible for approximately 3,200 deaths per year nationally.

Testing Your Calgary Home

Before you can know if mitigation is needed, you need a proper test. A long-term test (90+ days) is the gold standard — short-term tests (48–96 hours) are less reliable due to Calgary's notorious chinook pressure swings, which can cause dramatic day-to-day radon fluctuations. Long-term test kits run $30–$60 from hardware stores or online (Health Canada's C-NRPP certified kits). Place the detector in the lowest livable level of your home — your basement if it's developed or used regularly.

If you're buying a home, request radon testing as part of your home inspection. Many Calgary home inspectors now offer radon testing as an add-on for $150–$300.

Mitigation Costs in Calgary

If your results come back above 200 Bq/m³, sub-slab depressurization is the standard and most effective fix. A certified radon mitigation contractor installs a pipe through the concrete slab connected to a fan that draws radon from beneath the foundation and vents it outside. In Calgary, expect to pay $1,500–$3,500 for a typical installation, depending on your foundation type (slab vs. basement vs. crawlspace), sump pit configuration, and how many suction points are needed. Most installations drop radon levels by 80–99%.

The Canada Greener Homes Grant does not currently cover radon mitigation directly, but radon-resistant construction is increasingly being incorporated into new builds. Check nrcan.gc.ca for any updated program eligibility.

Always hire a C-NRPP certified radon mitigation professional (Canadian National Radon Proficiency Program) — this is the national certification standard for radon measurement and mitigation. You can find certified professionals at c-nrpp.ca.

Your next step: If you haven't tested your Calgary home, pick up a long-term radon test kit and run it through the fall and winter months when homes are sealed up — this gives you the most accurate reading. If you've already tested above 200 Bq/m³, browse the Calgary Construction Network directory to connect with a certified radon mitigation contractor in the Greater Calgary area.