The National Plumbing Code of Canada (NPC) is the model code that sets the technical rules for plumbing systems. Like the building and electrical codes, it has no force of law by itself. It only applies once a province adopts it, in full or with its own amendments. The in-force base across the country is the NPC 2020. A newer edition, the NPC 2025, was published on December 22, 2025, but it has not yet been adopted anywhere, so the NPC 2020 (with provincial amendments) is what governs plumbing work today.
How provinces adopt the plumbing code
The pattern mirrors the building code. The National Research Council publishes the NPC; the provinces decide whether and how to adopt it:
- Alberta is unusual. It adopted the NPC 2020 verbatim, with no provincial amendments at all, in force from April 1, 2023.
- Ontario folds the NPC 2020 into the 2024 Ontario Building Code, which came into force on January 1, 2025.
- British Columbia uses the NPC 2020 as its plumbing base inside the BC Building Code (in force March 8, 2024), with BC-specific amendments on top.
- Saskatchewan uses the NPC 2020 with Saskatchewan amendments.
- Quebec stands alone with its own Construction Code chapter on plumbing, based on the NPC 2020 but with Quebec changes, enforced by the RBQ.
- The remaining provinces adopt the NPC with some local variations.
The practical takeaway: a plumber works from the NPC 2020 almost everywhere, but must know where the local province has amended it.
Plumbing permits and who pulls them
Plumbing permits are part of the building permit system in most provinces, issued by the municipal building department, not a separate safety authority. The permit holder is the person responsible for code compliance:
- A licensed plumbing contractor applies for and holds the permit. In some cities the contractor also needs a municipal contractor licence.
- A homeowner can usually pull a plumbing permit for work on a home they own and occupy, often by signing a declaration that they will do the work. Some provinces limit this, for example to existing dwellings on private (non-communal) water and sewage systems.
A journeyperson working as an employee normally cannot pull a plumbing permit in their own name. See Getting a Building Permit for the general permit process.
Gas is a separate ticket
Plumbing and gas are not the same authorisation. Gas work carries the highest regulatory intensity of any trade because of fire and explosion risk, and gasfitter is a separate, compulsory trade in most provinces. A licensed plumber cannot connect a gas line unless they also hold the right gas credential.
- In Ontario, gas is regulated by the Technical Standards and Safety Authority (TSSA), separately from the municipal plumbing system. Technicians hold one of three certificates: G3 for basic residential appliances, G2 for residential and small commercial systems up to 400,000 BTUH input, and G1 for all gas work including large commercial and industrial systems over 400,000 BTUH. G2 is the standard ticket for residential HVAC and heating.
- In British Columbia, gas permits run through Technical Safety BC (or the municipality in some areas), and gasfitters hold a Class A or Class B Certificate of Qualification.
- In Alberta and Saskatchewan, gasfitter is a separate compulsory trade with its own permits, issued under the Safety Codes Act (Alberta) or through TSASK (Saskatchewan).
Backflow and cross-connection basics
A cross-connection is any point where the clean water supply could be contaminated by used or non-potable water, for example a hose left in a sink, an irrigation line, or a boiler feed. A backflow preventer is the device that stops contaminated water being drawn or pushed back into the drinking water supply when pressure drops or reverses.
The plumbing code requires backflow protection at cross-connection points, and many municipalities run their own cross-connection control programs that require testable backflow preventers to be installed, tested at installation, and re-tested on a schedule by a certified tester. Ongoing testing of installed assemblies is often the responsibility of the municipal water utility, not the provincial plumbing authority. Check the local program before specifying or installing a device.
Common mistakes
- Treating the NPC 2025 as current. It is published but not adopted anywhere. The NPC 2020 is the in-force base.
- Forgetting provincial amendments. Only Alberta adopted the NPC 2020 verbatim. Most provinces add changes.
- Assuming a plumbing licence covers gas. Gas is a separate, compulsory ticket almost everywhere.
- Skipping backflow protection. Cross-connection control is a code requirement and often a separate municipal program with testing obligations.
Know someone who needs this?
Keep reading
Was this guide useful?
Didn't find what you were looking for?
Spotted something wrong or out of date? Email us at hello@kilnguides.co.uk.
In crisis? 988 Suicide Crisis Helpline (call or text 988) ·