Radon in Calgary: Levels, Risk Factors & What to Do

Calgary has a real radon problem. A large-scale study of 2,382 southern Alberta homes found that 12.4% had radon levels at or above Health Canada's action level of 200 Bq/m³, with an average indoor level of 126 Bq/m³. That's roughly five times the national average of about 25 Bq/m³. If you own a home in Calgary and haven't tested, read on.

Calgary's radon levels by the numbers

The most detailed picture of Calgary's radon situation comes from a study conducted between 2013 and 2016, published in the Canadian Medical Association Journal Open. Researchers tested radon in over 2,000 homes across Calgary and surrounding communities.

Key findings from the CMAJ Open study of 2,382 southern Alberta homes:

• Average indoor radon in southern Alberta homes: 126 Bq/m³
• Average across Calgary's four quadrants: 115–122 Bq/m³
• Homes at or above 100 Bq/m³: 47.6% (nearly half of all homes tested)
• Homes at or above 200 Bq/m³: 12.4%

For comparison, Health Canada's national cross-Canada survey estimates roughly 1 in 11 Canadian homes exceeds 200 Bq/m³. In Calgary and southern Alberta, it's closer to 1 in 8.

More recent data from the Cross-Canada Radon Survey found that approximately 1 in 6 Calgary Metro Area homes has radon at or above 200 Bq/m³, with an average residential level of 102.5 Bq/m³. The numbers aren't improving.

Why does Calgary have elevated radon?

Radon forms when uranium and radium in soil and rock decay. Alberta's geology, dominated by uranium-bearing sedimentary rock and glacial soils deposited after the last ice age, produces radon at higher rates than most of Canada's bedrock.

The Foothills region west of Calgary introduces additional complexity. Rocky Mountain runoff has deposited coarse glacial till, sand, and gravel that allows radon-bearing soil gas to migrate toward the surface and into homes.

Cold winters compound the issue. Calgary homes are sealed for months at a time during heating season, so radon that gets in has nowhere to go. It builds up to higher concentrations than it would in a more ventilated home.

These factors combine to make Calgary one of the higher-risk major cities in Canada, comparable to Edmonton but with distinct variation depending on soil type and local geology.

Which areas of Calgary have the highest radon?

The CMAJ Open research showed real variation across Calgary's quadrants and into surrounding communities. The areas with the highest average indoor radon in the study:

• Cochrane: 261 Bq/m³ average, the highest in the study area
• Okotoks and High River: 194 Bq/m³ average
• Calgary's southwest quadrant showed slightly higher levels than the northeast, though all quadrants were well above the national average

That said, neighbourhood-level averages don't tell you much about your specific home. Radon levels depend primarily on the conditions under your foundation: soil permeability, foundation type (poured concrete vs. block vs. slab), and how well sealed the home is. Two houses on the same street can have dramatically different readings.

The only way to know your home's level is to test it.

Foundation type and your Calgary home's risk

In Calgary, the most common foundation types are poured concrete and concrete block. Both allow radon to enter through:

• Cracks in the foundation floor or walls
• Construction joints where floor meets wall
• Gaps around pipes, posts, and service penetrations
• Floor drains and sump pits (common in Calgary homes)

Homes with unfinished basements that people regularly occupy are particularly worth testing, since residents spend time at the floor level where radon concentrations are highest. The lowest livable level of any home will have the highest radon readings.

How to test your Calgary home

Health Canada recommends a long-term alpha track test: a small device left in place for at least 91 days, ideally during heating season (October through April) when windows are closed and radon concentrations are at their peak.

Option 1: Long-term mail-in test kit (~$30–$60)

The most accurate and most recommended approach for mitigation decisions. Place the device, leave it for 3+ months, then mail it to a certified lab. Results arrive within a week or two of receipt.

Option 2: Electronic continuous monitor (~$160–$350)

A digital monitor gives a live reading and tracks levels over time. C-NRPP approved models include the Airthings Corentium Home, Aranet RN+, and Ecosense RadonEye. Useful for ongoing monitoring, but leave them in place for at least 90 days before relying on the long-term average for decisions.

Place your test device in the lowest livable level of your home, away from drafts, exterior walls, and windows. Keep windows and doors closed as much as practical during the test period.

For more detail on choosing and placing a test device, see: How to test your home for radon.

What to do if your Calgary result is high

Health Canada's guidelines are clear:

Given Calgary's average of 115–126 Bq/m³, many homeowners will find their results in the 100–200 range. It's not an emergency, but it warrants attention, especially if family members spend a lot of time in the basement.

If your result is at or above 200 Bq/m³, the standard solution is sub-slab depressurization, a system that draws radon from beneath your foundation and vents it outside. When properly installed, these systems typically reduce radon levels by 80–99%. A certified professional can usually complete the installation in a single day, and the system runs quietly and continuously.

Cost of radon mitigation in Calgary

Calgary sits at the higher end of the national cost range due to construction complexity and labour markets.

• Sub-slab depressurization (typical home): $2,000–$3,500
• Complex configurations (finished basements, multiple suction points): up to $4,500
• Post-mitigation re-test: $30–$60 (do this 30–90 days after installation)

Get quotes from at least two certified professionals. All quotes should include a post-mitigation test to confirm the system is working.

For a detailed cost breakdown by province: How much does radon mitigation cost in Canada?

Radon in Calgary real estate

Radon testing in real estate transactions is more common in Calgary than it used to be, though it isn't legally required. Given the city's documented risk profile, buyers are increasingly including radon testing as a standard condition of purchase, particularly for homes with finished basements.

If you're buying in Calgary, including a radon test during the inspection period is inexpensive and sensible. If results come back high, you can negotiate mitigation costs with the seller, have it done before closing, or walk away. Sellers who've already tested and mitigated can use that as a genuine selling point.

For more on how radon intersects with home transactions: Radon and real estate in Canada.

Find a certified radon professional in Calgary

All professionals listed on RadonFinder.ca hold active C-NRPP certification, the national standard recognized by Health Canada. C-NRPP certification means they've passed standardized training in radon measurement and mitigation.

Browse certified radon professionals serving Calgary

When contacting a contractor, ask:

• Are you C-NRPP certified for both testing and mitigation?
• Does the quote include post-mitigation testing?
• How long will installation take?
• What warranty do you offer on the system?

Most Calgary-area professionals can book consultations within 1–2 weeks, with installation shortly after. During peak seasons (spring and fall), scheduling can stretch to 3–4 weeks.

The bottom line

Calgary has one of the higher radon risk profiles among major Canadian cities. The data is clear: roughly 1 in 8 homes exceeds Health Canada's action level, and nearly half exceed the WHO guideline of 100 Bq/m³. Testing is straightforward and inexpensive. If your result is elevated, the fix is permanent and works.

Start with a test. Everything else follows from knowing your number.

• Browse DIY radon test kits and monitors
• Find a certified radon professional in Calgary
• Use our radon situation assessment quiz