Radon in Quebec City (2026): What the Data Shows, Why It's High, and What Quebec Homeowners Should Do

Flat-vector map of Canada with a coral red pin marking Quebec City, Quebec, alongside a circular badge showing 18% — Quebec's recent provincial share of homes above the Health Canada radon guideline

A note before you read. This article is general health and home-testing information for Quebec City homeowners, drawn from Health Canada, the Gouvernement du Québec, the Association pulmonaire du Québec, the OACIQ (Organisme d'autoréglementation du courtage immobilier du Québec), and the Canadian Cancer Society. It is not medical advice and is not legal advice. See full disclaimers at the bottom.

If you live in the Quebec City region (Capitale-Nationale) and you've heard radon is a concern in some Quebec areas, the data confirms it. Quebec province has approximately 8% of homes above the Health Canada 200 Bq/m³ guideline per Health Canada's 2012 Cross-Canada Survey, but some Quebec regions have up to 25% of homes above the guideline — and more recent provincial data suggests nearly 1 in 5 Quebec homes (about 18%) now exceeds the guideline. In Quebec, 10–16% of lung cancer deaths are associated with radon exposure, representing more than 600 deaths per year.

What's distinctive about Quebec is the regulatory framework around real estate disclosure. The OACIQ (Quebec's real estate regulator) has set out specific clauses (D12.1, D12.2, D13.9 of the Declarations by the seller of the immovable form, mandatory since 2012) that require sellers to disclose prior radon tests and remediation. Quebec brokers can also withhold a sum from the sale proceeds if a radon report shows elevated levels — a Quebec-specific protective mechanism for buyers.

This guide walks through the Quebec data, explains why some Quebec areas have elevated radon, lays out the practical step-by-step from "I want to know" to "result in hand," and details the OACIQ disclosure framework along with other Quebec-specific resources.

TL;DR for Quebec City homeowners

  • Quebec province: about 8% of homes above the 200 Bq/m³ guideline (2012 Health Canada Cross-Canada Survey); some regions up to 25%; more recent data suggests nearly 1 in 5 (about 18%) Quebec homes now exceeds the guideline.
  • In Quebec, 10–16% of lung cancer deaths are associated with radon exposure — more than 600 deaths per year.
  • The only way to know your home's level is to test it. Long-term test, 91+ days, ideally during the heating season. Order a $89 long-term radon test kit →
  • Quebec brokers must disclose known radon results under OACIQ rules (clauses D12.1, D12.2, D13.9 — mandatory since 2012). Quebec is the only province with a published mechanism for withholding sale proceeds when a radon report shows elevated levels.
  • Mitigation works. Sub-slab depressurization typically reduces radon by up to 95% at a typical Quebec cost of $2,500–$4,500. The Canadian Lung Association's Lungs Matter program offers up to $1,500 for eligible Quebecers.

Table of contents

  1. What the published Quebec radon data actually shows
  2. Why Quebec City radon is elevated in some areas
  3. What to do as a Quebec City homeowner
  4. OACIQ disclosure rules — the Quebec real estate framework
  5. Local Quebec City and Quebec resources
  6. FAQ — Quebec City–specific questions
  7. Disclaimers
  8. Sources

What the published Quebec radon data actually shows

Quebec's residential radon picture has been studied through Health Canada's national survey, the Gouvernement du Québec's residential radon program, and provincial public-health data:

  • Quebec province (2012 Cross-Canada Survey): about 8% of homes above the 200 Bq/m³ guideline, with some regions reaching up to 25%.
  • More recent data: about 18% of homes tested in Quebec exceed 200 Bq/m³ — nearly 1 in 5.
  • Health impact in Quebec: 10–16% of Quebec lung cancer deaths are associated with radon exposure, representing more than 600 deaths per year in the province.
  • Provincial average residential basement radon: relatively low at about 37 Bq/m³, but with significant regional variation — some Capitale-Nationale, Mauricie, Outaouais, and Estrie regions show notably higher levels.

Sources: Health Canada Cross-Canada Survey; Gouvernement du Québec — Residential radon; Take Action on Radon — Quebec

The takeaway: Quebec is not a uniformly low-radon province — some regions have rates that meaningfully exceed the national average, and the Quebec City area sits in a part of the province where elevated radon is documented in higher-than-average proportions of homes. The only way to know your specific home's level is a long-term radon test.

Order a $89 long-term radon test kit →

Why Quebec City radon is elevated in some areas

Three factors influence the Quebec City–region radon profile:

1. Geology. The Quebec City region sits at the edge of the Canadian Shield (to the north and northwest) and the St. Lawrence Lowlands (along the river). Areas underlain by Shield bedrock, particularly to the north and west of Quebec City, contain uranium-bearing rock that produces meaningfully higher background radon than the sedimentary rock under the Lowlands. This means radon levels can vary substantially across Quebec City–region neighbourhoods depending on local geology.

2. Climate. Quebec City has a long heating season — typically October through April — with cold winter temperatures and significant snow accumulation that lead to homes being sealed against the weather. Furnaces and HVAC systems run regularly, and the natural "stack effect" (warm air rising through the home creating negative pressure at the lowest level) actively pulls soil gas into basements.

3. Building construction. Quebec City housing stock includes many full-basement single-family homes and a substantial proportion of older urban housing, with various levels of foundation tightness and ventilation. Modern Quebec construction since 2012 has been subject to provincial code requirements for radon-aware features — but most existing housing predates these requirements.

The combination — variable geology with documented Shield-area hotspots + a long heating season + diverse housing stock — is why Quebec City and the broader Capitale-Nationale region show notable residential radon variability.

What to do as a Quebec City homeowner

Step-by-step:

Step 1: Test (long-term, 91+ days). Health Canada's recommended test for a homeowner mitigation decision is a long-term alpha-track lab test, deployed for at least 91 days during the heating season (October–April in Quebec City), in the lowest lived-in level of your home. The test costs $89 all-in with RadonTest.ca — kit, tracked outbound, prepaid tracked Canada Post return label, and analysis at Lex Scientific in Guelph, Ontario (a C-NRPP-listed Canadian lab). The Association pulmonaire du Québec also offers radon information and resources.

Step 2: Read your result. Below 200 Bq/m³, no mitigation is required (Health Canada recommends retesting every 5 years). Above 200 Bq/m³, mitigation is recommended. See our How to Read Your Radon Test Results and What to Do If Your Radon Level Is Above 200 Bq/m³ guides.

Step 3: Mitigate, if needed. A C-NRPP-certified mitigation contractor installs a sub-slab depressurization system at a typical Quebec cost of $2,500–$4,500. These systems typically reduce radon by up to 95%. Find a Quebec City–area C-NRPP-certified mitigator via the C-NRPP Find a Professional tool.

Step 4: Apply for the Lungs Matter grant. The Canadian Lung Association's Lungs Matter program offers up to $1,500 toward radon mitigation for eligible Canadian homeowners, including Quebecers.

Step 5: Verify. Once mitigation is complete, run an independent post-mitigation test to confirm levels are below 200 Bq/m³ and stay that way.

Order your Quebec City kit — $89 →

OACIQ disclosure rules — the Quebec real estate framework

Quebec is distinctive among Canadian provinces for the explicit role its real estate regulator (OACIQ) plays in radon disclosure. Quebec real estate brokers are required to ask sellers about prior radon tests and remediation, and to disclose past expert results to prospective buyers (clauses D12.1, D12.2, D13.9 of the Declarations by the seller of the immovable form, mandatory in Quebec since 2012). (OACIQ Radon Practices Guide)

The OACIQ also describes a distinctive Quebec mechanism: if a radon measurement report states that the average annual radon concentration is equal to or exceeds 200 Bq/m³, a sum can be withheld from the proceeds of sale to the buyer — a provincial-specific protective tool that doesn't exist in the same form in other Canadian provinces.

For Quebec sellers, buyers, and brokers, the practical implications:

  • Sellers: if you've tested and found elevated radon, your broker is required to disclose it to prospective buyers under the mandatory declaration clauses. Pre-listing remediation can resolve the issue before the home is shown.
  • Buyers: ask explicitly whether the seller has ever tested, and request the lab report. If the result was above 200 Bq/m³, you have grounds to negotiate either pre-closing remediation or a withholding from sale proceeds for post-closing remediation.
  • Brokers: OACIQ's professional practices guide (oaciq.com) sets out the obligations explicitly.

For the cross-Canada framework on real estate radon disclosure, see our Real Estate Radon Guide. For Quebec-specific transactions, consult a Quebec real estate lawyer (notaire or avocat).

Local Quebec City and Quebec resources

  • Gouvernement du Québec — Residential radon (quebec.ca/.../residential-radon) — provincial government's residential radon resource page
  • Association pulmonaire du Québec — Radon (poumonquebec.ca/.../radon) — provincial non-profit's radon program
  • OACIQ — Radon Professional Practices Guide (oaciq.com/.../radon) — Quebec real estate broker disclosure framework
  • Take Action on Radon — Quebec (takeactiononradon.ca/provinces/quebec)
  • Canadian Lung Association — Lungs Matter mitigation grant (lung.ca) — up to $1,500 for eligible Canadians
  • C-NRPP Find a Certified Professional (c-nrpp.ca) — Quebec City–area certified measurement and mitigation professionals

Note on Quebec building code. Quebec uses the Code de construction Chapter I (updated April 17, 2025). The code requires sub-slab depressurization rough-in, soil gas barrier, sealed penetrations, and labelled radon piping in new construction. Garantie GCR added a full passive stack standard in November 2025. Quebec radon construction requirements have been in force province-wide since June 2023. See our Canadian Building Codes and Radon guide.

FAQ — Quebec City–specific questions

How common is high radon in Quebec City? Quebec province has about 8% of homes above the 200 Bq/m³ guideline (2012 Cross-Canada Survey), with some regions reaching up to 25%. More recent data suggests nearly 1 in 5 Quebec homes (about 18%) now exceeds the guideline. The Capitale-Nationale region sits in a part of Quebec where elevated radon is documented in higher-than-average proportions of homes. The only way to know your specific home's level is to test it.

Why are some Quebec City areas higher than others? Quebec City sits at the edge of the Canadian Shield and the St. Lawrence Lowlands. Areas underlain by Shield bedrock (north and northwest) contain uranium-bearing rock that produces meaningfully higher background radon than sedimentary Lowlands rock. Combined with a long heating season and varied housing stock, this produces substantial neighbourhood-level variability.

Are some Quebec City neighbourhoods worse than others? Yes, in broad terms — Shield-influenced areas tend to be higher. But individual home levels vary substantially even within neighbourhoods, and the only way to know your specific home's level is to test it.

What does the OACIQ require Quebec brokers to disclose about radon? Per OACIQ's Radon Practices Guide, Quebec real estate brokers must ask sellers about prior radon tests and remediation, and must disclose past expert results to prospective buyers. The relevant clauses (D12.1, D12.2, D13.9) of the Declarations by the seller form have been mandatory in Quebec since 2012.

Can I withhold sale proceeds for radon mitigation in Quebec? Yes — the OACIQ has described that if a radon measurement report shows an average annual concentration at or above 200 Bq/m³, a sum can be withheld from the proceeds of sale to the buyer. This is a Quebec-specific protective mechanism. Consult a Quebec notaire or real estate lawyer for the specific structuring of any withholding arrangement.

How much does radon mitigation cost in Quebec City? Typical Quebec residential mitigation costs are $2,500–$4,500 for a sub-slab depressurization system installed by a C-NRPP-certified contractor. The Canadian Lung Association's Lungs Matter program may offset up to $1,500.

Where can I buy a long-term radon test kit in Quebec City? You can order a RadonTest.ca $89 all-in long-term kit online and receive it within a few business days anywhere in the Quebec City area — kit + tracked outbound + prepaid tracked Canada Post return label + analysis at a C-NRPP-listed Canadian lab. The Association pulmonaire du Québec (poumonquebec.ca) also offers Quebec-specific radon resources.

Does my newer Quebec City home have radon-aware construction? If your home was built under Quebec's Code de construction radon provisions (in force province-wide since June 2023), it should have sub-slab depressurization rough-in, a soil gas barrier, sealed penetrations, and labelled radon piping. Newer GCR-warranted homes (post-November 2025) include a full passive stack standard. The rough-in / passive stack is infrastructure that makes future active mitigation easier, but does not always reduce radon to levels below the Health Canada guideline of 200 Bq/m³ on its own.

When is the best time of year to test in Quebec City? The heating season — October through April — produces the highest indoor radon levels and is the recommended testing window per Health Canada. A long-term test (91+ days) started in early October gives you a strong heating-season reading.

Where can I find a C-NRPP-certified radon mitigator in Quebec City? The C-NRPP Find a Certified Professional directory lists certified measurement and mitigation professionals by area.

Test your Quebec City home — $89, all in

Quebec province has documented residential radon variability, the Capitale-Nationale region falls in a part of Quebec where elevated levels are more common, and the action item is the same one any Canadian homeowner should take: a long-term radon test that produces a real lab result.

RadonTest.ca — $89 all-in (plus applicable tax). Long-term 91-day alpha-track test kit. C-NRPP-listed device. Analysed at Lex Scientific in Guelph, Ontario — Canadian lab, C-NRPP listed, ISO/IEC 17025 accredited by CALA. Tracked Canadian shipping both ways. Written lab report PDF delivered to your inbox.

Order — $89 →

Important disclaimers

Not medical, legal, or warranty advice. This article provides general health and home-testing information for Quebec City homeowners drawn from publicly available Health Canada, Gouvernement du Québec, Association pulmonaire du Québec, OACIQ, and Canadian Cancer Society materials. It is not medical advice, legal advice, or warranty advice. Consult a qualified professional for specific decisions.

Statistics and citations. The 8%/up-to-25% Quebec figure is from Health Canada's 2012 Cross-Canada Survey of Radon Concentrations in Homes. The 18% / "nearly 1 in 5" figure reflects more recent provincial data. Health impact figures are cited as published by Quebec public-health sources. National figures are from Health Canada's Radon: What You Need to Know fact sheet (2025). Sources update published figures periodically; figures cited reflect the sources as of May 2026.

Local Quebec City data. Statements about Quebec radon levels reflect published research and government materials. Radon levels vary substantially even between adjacent homes; community-level statistics do not substitute for a home-specific long-term test.

OACIQ disclosure framework. Statements about OACIQ broker obligations and the sale-proceeds withholding mechanism reflect publicly available OACIQ guidance materials. Specific obligations and structuring for any individual Quebec real estate transaction depend on the facts; consult a Quebec notaire or real estate lawyer (avocat).

Mitigation cost. The $2,500–$4,500 mitigation cost range is a typical Quebec residential figure. Actual costs vary by home, foundation, complexity, and contractor.

Lungs Matter grant. Eligibility, grant amounts, and program availability for the Canadian Lung Association's Lungs Matter program may change. Verify directly at lung.ca before relying on the program.

No diagnosis or treatment claims. RadonTest.ca sells radon test kits. We do not diagnose, treat, or prevent disease.

No warranty as to completeness. RadonTest.ca makes no warranty as to the completeness or accuracy of the information herein and accepts no liability for decisions made in reliance on this article.

Sources & further reading

Quebec- and Quebec City–specific

Health Canada / national

National associations and grants

Related RadonTest.ca articles