Does the Quebec Building Code protect against radon? Only partly. Since June 2, 2022, the Code has required a sub-slab pipe and a passive extraction column in the new buildings it covers — "rough-in" infrastructure that gets the home ready. But that passive column does not lower radon on its own: it only reduces the concentration once it is activated with a fan, and only if a test reveals an elevated level. The only way to know the radon level in your home — even a brand-new, code-compliant one — is still a long-term test (alpha-track kit, 91 days or more).
This article explains, with official sources, exactly what the Code requires, the difference between a passive and an active system, and why a new code-compliant home still has to be tested.
What Quebec's Building Code Has Required Since 2022
Here is the exact timeline, taken directly from the Régie du bâtiment du Québec (RBQ).
The amendments to Chapter I, Building, of the Construction Code (which adopts the National Building Code of Canada 2015, Quebec-amended) were adopted in November 2021 and came into force on January 8, 2022. A second amendment, which extends the scope of subsurface-gas protection measures to the entire territory of Quebec, was published in the Gazette officielle on May 18, 2022, and came into force on June 2, 2022.
That second amendment is the most important one for radon: it removes the notion of "recognized at-risk zones." Previously, the measures were required only in certain targeted regions; since June 2, 2022, they apply everywhere in Quebec. As the RBQ explains, this decision follows the recommendations of Quebec's public-health authorities and Health Canada, because radon "has no borders": two neighbouring homes can show very different concentrations, and no map can predict the level of a specific building.
And the "transition period" that causes the confusion? This is what explains why some sources refer to "2023." An 18-month transition period was provided. In practice:
- Buildings whose work began between January 8, 2022, and July 7, 2023 could comply with either the old or the new edition of the chapter.
- Buildings whose work begins on or after July 8, 2023 must comply with the new edition.
In other words: the rule has been in force since 2022, but it became unavoidable for every project as of July 8, 2023.
| Date | What happens |
|---|---|
| January 8, 2022 | Chapter I, Building (NBC 2015, Quebec-amended) comes into force |
| June 2, 2022 | The amendment extending subsurface-gas measures to all of Quebec comes into force (removal of the "at-risk zones") |
| January 8, 2022 – July 7, 2023 | Transition period: old or new edition accepted |
| July 8, 2023 and after | Compliance with the new edition mandatory for all work |
Sources: RBQ, "Building Chapter of the Quebec Construction Code in force from 2021 to 2025" and the press release of May 18, 2022 (links at the end of the article).
What Exactly Does the Code Require? (the technical detail)
The Code no longer settles for a simple "capped pipe roughed-in and waiting." In many cases, it now requires a complete passive extraction column from the moment of construction. According to the technical documentation published by Québec habitation (the blog of the Association des professionnels de la construction et de l'habitation du Québec, or APCHQ), here are the requirements that builders must build into a new home.
The passive extraction column must:
- be connected to the piping located beneath the concrete slab;
- run vertically through the building;
- vent above the roof;
- be at least 10 ft away from windows, doors, and air intakes.
Specific technical requirements are added:
- non-perforated duct;
- minimum diameter of 4 in (about 100 mm);
- compliant materials (PVC schedule 40);
- mandatory insulation in unheated sections, particularly in the attic, to ensure good performance from the passive column;
- mandatory identification of the duct.
On this last point, the Code requires that the radon extraction duct be clearly identified to avoid any confusion with other mechanical or plumbing systems. This identification must be placed at regular intervals and at every change of direction, using stickers indicating the duct's function. It is a measure for safety, compliance, and future maintenance.
To this is added, beneath the slab, a membrane (an air-sealing system) meant to prevent the infiltration of subsurface gases, along with the sealing of penetrations through the slab. Together, this forms infrastructure ready to receive a fan later on — if a test warrants it.
The takeaway: all of this work prepares the home. It does not actively "capture" or "remove" radon until a fan has been added. This is exactly where testing comes in.
Passive System or Active System: What's the Difference?
This is the most important distinction in this article, and the one the word "mandatory" so often makes people forget.
A passive system (what the Code requires) is a vertical column, with no fan, that relies on simple natural draft (the stack effect) to let radon escape toward the roof. According to the reference documentation, a passive system can reduce the concentration by about 50% — a real improvement, but a partial one, and not guaranteed.
An active system adds a fan that runs continuously to actively depressurize the soil beneath the slab. It is the most effective measure: it can reduce radon concentrations by more than 90%. But adding the fan — the "activation" — is not automatic: it depends on a test result.
| PASSIVE column / system (required by the Code) | ACTIVE system (a fan is added) | |
|---|---|---|
| Fan | None | Yes, continuous |
| Installed when? | At construction (mandatory) | Later, if a test warrants it |
| Radon reduction | Partial (~50%), not guaranteed | High (often > 90%) |
| Trigger | — | Long-term test > 200 Bq/m³ |
| Guarantees a low level? | No | Strongly reduces; reconfirm with a test |
So the Code prepares the radon "plumbing." It is then up to the homeowner to verify, through a test, whether that plumbing needs to be put under pressure by a fan.
Why Isn't the Mandatory Radon Pipe Enough?
For three concrete reasons.
1. A passive column is not a guarantee of a low radon level. It reduces radon "on average" and "in many cases," but the real performance depends on the home, the soil, the air-tightness, and the weather. No official source promises that a passive column will bring your home below the action level. In fact, Health Canada is unequivocal: there is no radon level free of risk. The 200 Bq/m³ figure is a guideline indicating the point at which you should take action — not a risk-free threshold below which you can stop worrying.
2. Radon is unpredictable from one home to the next. This is the very reason the Code removed the "at-risk zones": you cannot predict a building's concentration from its neighbour or its region. A new, compliant, well-built home can still exceed 200 Bq/m³.
3. The Code does not require you to measure. This is the point housing experts raise: the regulation requires the infrastructure, but nothing in the Code requires you to test the finished home or to activate the system. As Écohabitation sums it up, only an analysis of the indoor air in the finished building can determine the concentration. Until a test has been done, no one — not the builder, not the RBQ, not you — knows the real level.
This is exactly why public-health authorities recommend that all homeowners test their home, new or not.
My Home Is New and Code-Compliant. Do I Still Need to Test?
Yes. A home built to the Code starts with an advantage: the passive column is already in place, and a future activation will cost much less (you only have to add a fan, without having to drill through the slab after the fact). But that advantage does not replace the measurement.
Here is what to do, in line with Health Canada's recommendations:
- Wait until you are living in the home. Ideally, measure during the first heating season after you move in, when the home is closed up and radon tends to accumulate.
- Do a long-term test. Health Canada recommends a test lasting at least 3 months (91 days), because radon varies enormously from day to day and from season to season. A short test of a few days can be misleading.
- Read the result against 200 Bq/m³. If the annual average exceeds the 200 Bq/m³ guideline, Health Canada recommends taking corrective measures within one year to bring the level down "as low as reasonably achievable."
- Activate if needed. Because the passive column is already installed, mitigation essentially comes down to converting it into an active system by connecting an extraction fan, and then re-testing to confirm that the level has indeed dropped.
To learn exactly where to place the kit in your home, see our guide, Where to Place a Radon Test Kit. And if your result exceeds the guideline, see What to Do if Your Radon Level Is Above 200 Bq/m³.
Our alpha-track radon test kit is designed for exactly this kind of measurement: a long-term detector (91 days and up), analyzed by a C-NRPP-certified laboratory in Canada, with prepaid return — all you do is drop it in the mail. It is the tool that turns a "code-compliant" home into a verified one.
How to Test and Activate Depressurization, Step by Step
| Step | Action | Who / what |
|---|---|---|
| 1 | Move in and wait for the heating season | Homeowner |
| 2 | Place an alpha-track kit on the lowest occupied living level | Kit ≥ 91 days |
| 3 | Return the kit to the laboratory (analysis in Canada) | C-NRPP-certified lab |
| 4 | Compare the result to 200 Bq/m³ | Health Canada guideline |
| 5a | Result < 200 Bq/m³: no activation required (re-test periodically) | Homeowner |
| 5b | Result ≥ 200 Bq/m³: have the passive column activated (a fan is added) | Mitigation professional |
| 6 | Re-test to confirm the reduction | New kit |
The good news for new, compliant homes: because the passive column and sub-slab piping are already there, the cost of activation is generally far lower than for an existing home, where you have to drill through the slab and install all the piping. The job often comes down to connecting a fan to the column that is already in place. (Mitigation costs vary by home, foundation type, and contractor: ask a professional for a quote.)
Is Quebec Ahead of the Rest of Canada?
Yes. By requiring these measures across its entire territory back in 2022, Quebec positioned itself as a front-runner in Canada. Most other provinces do not yet require, at the provincial level, radon infrastructure in every new home.
The picture is changing at the national level, however. The National Building Code of Canada 2025 incorporates strengthened radon provisions — notably the addition of a vertical passive extraction column to the base system, mandatory identification of the duct, and improved sealing of openings. As provinces adopt the 2025 Code, these requirements will become more widespread across the country. Quebec, for its part, has already been applying the gist of this logic since 2022.
Also worth noting: the Garantie de construction résidentielle (GCR) has published its own technical sheet for subsurface-gas protection, along with a passive-column standard that applies to new homes covered by the warranty. If you are buying a new home in Quebec, these protections may concern you: see our article on the GCR new-home warranty and radon in Quebec.
| Quebec | Rest of Canada (before the NBC 2025) | |
|---|---|---|
| Radon infrastructure mandatory in new homes | Yes, everywhere, since 2022 | Varies; often not required at the provincial level |
| Removal of the "at-risk zones" | Yes (whole territory) | Depends on the province |
| National direction | — | The NBC 2025 generalizes similar requirements |
For the Canada-wide picture of the codes, see our guide to Canadian building codes and radon. And for the case of new homes in general, see radon in new-construction homes in Canada.
There is also a related Quebec question for parents and operators: the rules for radon in schools and daycares in Quebec follow their own track.
Frequently Asked Questions
Does the Quebec Building Code make radon testing mandatory? No. The Code requires infrastructure (sub-slab piping and a passive extraction column) in the new buildings it covers, but it does not require the homeowner to measure radon once the home is finished. Testing remains voluntary — and is strongly recommended by Health Canada and Quebec's public-health authorities.
Since when has the radon pipe been mandatory in Quebec? The amendment extending subsurface-gas protection measures to all of Quebec came into force on June 2, 2022. After a transition period, compliance became mandatory for all projects beginning on or after July 8, 2023.
Does the passive column required by the Code eliminate radon? No. A passive column, with no fan, reduces radon partially (often around 50%) and without any guarantee. For a significant reduction, you generally have to activate the system by adding a fan — a step that depends on a test result above 200 Bq/m³.
My new home is code-compliant. Do I still need to test for radon? You cannot know without testing. Health Canada points out that there is no radon level free of risk and that you cannot predict a home's concentration from its region or its neighbours. Even a new, compliant home can exceed 200 Bq/m³. Only a long-term test confirms it.
What is the radon threshold in Quebec? Quebec aligns with Health Canada's guideline: 200 Bq/m³ (annual average). Above this figure, Health Canada recommends taking corrective measures within one year. It is not a risk-free threshold, but an action threshold.
How long should a radon test last? At least 3 months (91 days), ideally during the heating season. Short tests are less reliable, because radon varies a great deal from day to day and from season to season.
What is sub-slab depressurization? It is the most common mitigation technique: radon-laden air is drawn out from beneath the concrete slab and vented above the roof, which keeps the gas from entering the home. The passive version (provided for by the Code) relies on natural draft; the active version adds a fan for far greater effectiveness.
Order your radon test kit → — all-in, analyzed in Canada, prepaid return shipping.
Sources
- RBQ — Building Chapter of the Quebec Construction Code in force from 2021 to 2025 — dates of coming into force (January 8, 2022 and June 2, 2022), the 18-month transition period, covered buildings, adoption of the NBC 2015 Quebec-amended, "install base piping beneath a floor slab."
- RBQ — Press release: Regulation amending the Construction Code, subsurface-gas protection measures for all of Quebec (May 18, 2022) — coming into force on June 2, 2022, removal of the "recognized at-risk zones," end of the transition period on July 8, 2023.
- Québec habitation (APCHQ) — Radon: what the new Construction Code requirements change in Quebec — detailed technical requirements: complete passive extraction column, sub-slab connection, venting above the roof, distance of at least 10 ft from openings, non-perforated duct, 4 in diameter, PVC schedule 40, mandatory insulation in the attic, identification with stickers.
- Écohabitation — Radon: a new standard for new buildings — the move from 800 to 200 Bq/m³ in Quebec, passive/active levels, a level-3 fan, and the key message: only an analysis of the air in the finished building determines the concentration; all homeowners should test.
- Health Canada — Canada's Radon Guideline (200 Bq/m³) — the 200 Bq/m³ guideline, no risk-free level, corrective measures within one year, lowering "as low as reasonably achievable."
- Health Canada — Guide for Radon Measurements in Residential Dwellings — long-term test of at least 3 months, ideally during the heating season.
- Health Canada — Radon Action Guide for Municipalities: building codes — context: installing sub-slab piping, an air-barrier membrane, depressurization activated if the concentration becomes a problem.
- NRC — National Building Code of Canada 2025 — national direction: gradual generalization of radon requirements as provinces adopt the 2025 Code.
This article is provided for information purposes and does not constitute legal or technical advice. For the requirements that apply to your specific project, confirm with the Régie du bâtiment du Québec or a qualified professional. RadonTest.ca is not affiliated with the RBQ or Health Canada.