Tax Guide for Self-Employed Plumbers (Canada 2025)
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Guidance, not advice. We explain the rules, we don't assess your situation. Always seek financial or tax advice from your accountant, or contact CRA. Read our editorial scope →
Provincial licensing & certification
| Jurisdiction | Requirement |
|---|---|
| Ontario | OSTA Certificate of Qualification (compulsory trade 306A); separate Gas Technician G2/G3 via TSSA for any gas work |
| British Columbia | SkilledTradesBC certification mandatory (1 Dec 2023+); Technical Safety BC gas fitter ticket for gas |
| Alberta | AIT plumber journeyperson certificate; gas fitter Class B for natural gas / propane |
| Québec | RBQ licence + Emploi-Québec plumbing competency card; gas work needs separate Class 5 RBQ subcategory |
| Atlantic provinces | Provincial apprenticeship boards; Red Seal recognised inter-provincially |
Trade-specific deductible expenses
- Pipe threading machines, soldering torches, press tools — Class 8 (20% DB) over $500; Class 12 (100%) under $500
- Drain-cleaning equipment (snakes, jetters) — Class 8 for major units
- Diagnostic cameras & locators — Class 8
- Materials — copper, PEX, fittings, fixtures: COGS deducted when used on jobs (or inventoried if held at year-end)
- TSSA / RBQ / OSTA renewal fees — fully deductible
- Apprentice wages — Apprenticeship Job Creation Tax Credit (10%, max $2,000/yr)
- Safety gear — knee pads, respirators, gloves, hearing protection
Vehicle expenses
Work vans with permanent racks for pipe storage typically Class 10 (30%). Keep a logbook. Service-call travel between sites is business; home-to-shop is personal. Track parking + tolls separately.
GST/HST
Plumbing services are taxable supplies. Register at $30k trailing four quarters. Most residential repair work is fully taxable (no rebate). New-home rough-in plumbing supplied to a builder is still taxable at full rate; the builder claims input tax credits.
WSIB / WCB coverage
Mandatory for construction plumbers in Ontario (WSIB), BC (WorkSafeBC), Québec (CNESST). In Alberta/SK/MB, mandatory once you have employees; sole-operator owners can elect personal coverage. Service-only plumbers (not classed as construction) may face different premium classes — confirm with the provincial board.
CRA audit focus for this trade
What gets flagged
- Cash jobs missing from gross revenue (CRA cross-checks supplier purchase data)
- Personal house bathroom renovations charged to the business
- Treating an apprentice as a "subcontractor" to avoid CPP/EI
- Claiming 100% vehicle use without a logbook
- Failing to register for GST/HST after crossing $30k
Worked example
BC service plumber — $95,000 gross
Gross revenue $95,000
Materials (parts marked-up to client) ($22,000)
Van (75% biz of $6,800) ($5,100)
Tools, TSSA renewal, WorkSafeBC ($3,800)
Phone, dispatch software ($1,900)
Home office ($1,500)
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Net self-employment income ≈ $60,700
CPP ≈ $6,900
Federal + BC tax ≈ $9,200
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Take-home ≈ $44,600
GST + PST collected (BC: 5% + 7%) separate remittances
Related calculators & references
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