Quebec's radon risk is concentrated in regions underlain by the Grenville geological province, including the Laurentians, Eastern Townships, the Outaouais, and parts of Mauricie, where uranium-bearing gneiss and granite produce elevated soil gas. The Montreal urban area, sitting on the St. Lawrence Lowlands, generally shows lower levels. Quebec has a high proportion of older housing stock in cities like Quebec City and Trois-Rivières, and older construction with block foundations and open sump pits tends to allow more radon entry.

Typical Mitigation Cost in Quebec

$2,200–$3,600

Near national average

Montreal-area labour rates apply in the urban corridor; rural and Laurentian regions may see higher costs due to contractor travel.

•Foundation type: block, poured concrete, or stone foundations in older Quebec homes
•Open sump pits and floor drains as radon entry points
•Finished vs. unfinished basement: finishing adds pipe-routing complexity
•Bilingual service availability in some rural areas
•Age of home: pre-1980 homes often require more sealing work

Local radon data

How common is high radon in Quebec?

Moderate

1 in 5.3

homes in Quebec have radon above Health Canada's action level of 200 Bq/m³. That's about the same as Canada as a whole (1 in 5.6).

Check your postal code on the radon map

Cities in the 2024 survey

Sherbrooke1 in 4.3 homes
Québec1 in 5.6 homes
Montréal1 in 6.3 homes

Are you a radon professional in Quebec? Claim and verify your free listing.

Learn more →

Frequently Asked Questions: Radon in Quebec

The Laurentians, Eastern Townships (Estrie), Outaouais, and Mauricie regions tend to have higher radon due to Grenville-province geology. Communities like Gatineau, Sherbrooke, and Shawinigan are in elevated-risk zones. Montreal sits on lower-risk sedimentary geology but local variations exist.

Radon testing is not legally required in Quebec real estate transactions. The Outaouais region near Ottawa has higher awareness, but testing is not yet as routine as home inspections in most Quebec markets.

Quebec follows Health Canada's national guideline of 200 Bq/m³. There is no separate provincial standard. The Quebec Ministry of Health supports Health Canada's testing and mitigation recommendations.

Yes. Stone foundations common in older Quebec homes and concrete block foundations have many natural gaps and joints through which radon can enter. These homes often benefit from both air-sealing and a sub-slab or sub-membrane depressurization system.

Radon enters homes year-round, but levels are typically higher in winter when homes are sealed against the cold. Health Canada recommends testing during the heating season for the most representative result.

A standard active sub-slab depressurization installation takes one day in most cases. Older homes with complicated foundations or multiple entry points may require additional sealing work that extends the project.

Yes. Certified radon professionals operate throughout Quebec, including in Montreal, Quebec City, Gatineau, Sherbrooke, and many other regions. Use the city search above to find a certified professional near you.

Most Quebec homeowners pay between $1,800 and $3,200 for a complete mitigation system. Older homes may require additional sealing work that adds to the total cost.

Radon Resources for Quebec

Tools and guides to help you understand radon risk and take action.

Check your radon risk

Estimate your risk based on province, home age, and foundation type.

Understand your test results

Learn what Bq/m³ means and when action is required.

DIY radon test kits

Compare test kit options starting from $10.

Radon guides & articles

In-depth guides on testing, mitigation, and health risk.

Radon map of Canada

See how common high radon is in your postal code.

Radon FAQ

Answers to the most common questions about radon.