Canada does not have one national ADU code that every province applies unchanged. Provinces adopt national model codes on their own schedules, add provincial amendments, and define project transitions. Local authorities administer permits and determine how a proposed unit and its work are classified. This overview was checked against the listed official provincial sources on October 17, 2026; it is an edition-finding aid, not a compliance decision for a particular property.
Provincial code checkpoints
| Province | Official checkpoint | Date or project detail to verify |
|---|---|---|
| British Columbia | The Province identifies the BC Building Code 2024. | The Province ties specified earthquake and adaptable-dwelling provisions to permit applications on or after March 10, 2025. That date does not, by itself, determine every code provision for every project. Vancouver has a separate municipal by-law; see the City’s current energy-code path. |
| Alberta | Alberta lists the National Building Code — 2023 Alberta Edition, second printing, as in force. | Confirm the edition and any transition that applies to the permit record. A provincial code listing does not establish municipal land-use permission for a secondary suite. |
| Saskatchewan | The Province identifies the 2020 National Building Code, National Energy Code for Buildings, and National Plumbing Code as adopted from January 1, 2024. | Confirm the local authority and which code family applies to the specific work. Saskatchewan describes administration and enforcement as shared between the Province, local authorities, owners, and professionals. |
| Manitoba | Manitoba Regulation 78/2023 adopts the 2020 National Building Code with provincial amendments; the Province also identifies 2020 building, plumbing, energy, and fire-code adoptions from January 1, 2024. | For older permits, check the approved plans and inspection history. Manitoba’s guidance says inspections for permits approved before that date are assessed against the plans approved under the previous codes. |
| Ontario | Ontario Regulation 163/24 adopts the 2020 National Building Code with Ontario amendments dated July 17, 2026. | Section 2 has specific transition tests for earlier permits or qualifying drawing and application histories, including commencement conditions. Check the current consolidation and project file. |
| Québec | The Régie du bâtiment du Québec describes Chapter I, Building, as the 2020 National Building Code modified for Québec, effective April 17, 2025. | Its transition guide says earlier provisions may apply to covered work that began before October 17, 2026. Confirm that date against the current legal text and the project’s start record. |
| New Brunswick | Regulation 2021-2 adopts the 2020 National Building Code and National Energy Code for Buildings; it sets Tier 2 as the minimum for the cited energy provisions. | The cited consolidation is dated May 1, 2025. It describes a limited NBC 2015 transition for permits issued by March 31, 2025, with work-start and interruption conditions. Check for later amendments and treat the transition as a permit-history question, not an open choice for new work. |
| Nova Scotia | The current provincial regulations apply the 2020 National Building Code. The Tier 2 building-code provisions took effect April 1, 2026. | Check the current consolidation for the applicable code tier and project dates; later energy-code and Tier 3 dates are separate steps in the provincial schedule. |
| Prince Edward Island | The Province says Tier 1 of the 2020 National Model Codes took effect March 31, 2024, including the National Building Code and National Energy Code for Buildings. | A provincial announcement described projects then underway as continuing under 2015 editions but did not define every transition test. Ask the responsible authority how it treats an older or changed project. |
| Newfoundland and Labrador | A provincial circular says the 2025 National Building Code and National Fire Code came into force July 12, 2026. | The circular establishes those two code families; it does not determine every plumbing, energy, local, or ADU-classification question. Confirm the complete applicable code set. |
Use the links in the table to check the current instrument, not just a summary or a model-code publication. Some provincial sources are regulations; others explain implementation. A source’s edition date does not decide whether a project qualifies for a transition.
Match the code to the project record
Before comparing an ADU plan to technical requirements, identify the municipality or other authority that accepts the application. Describe whether the work is a new detached building, an addition, a suite within a house, a conversion, an alteration, or work on a previously permitted unit. Ask which occupancy or building classification the authority will use, which edition and provincial amendments apply, and whether a permit, drawing, or work-start date changes the answer.
Keep building-code approval separate from zoning permission, fire review, utility capacity, and any required inspections or completion record. A unit called an ADU in a zoning by-law may be classified differently for building-code purposes. The provincial examples above do not establish that a parcel permits a unit or that any design complies. For the general authority and classification sequence, see the guide to finding an applicable code edition.
Check transitions before relying on an older edition
Record the exact application, permit, drawing-completion, and work-start dates that the provincial rule names. Keep copies of the permit and approved plans, and ask how later changes, a work stoppage, or an incomplete inspection affect the transition. This matters especially for dates that have already passed: Québec’s October 17, 2026 work-start boundary and New Brunswick’s March 31, 2025 permit boundary are not general permissions to select an earlier code today.
Code editions and amendments change. Recheck the provincial regulation and the local authority’s current permit instructions before using this overview for a live project.