Who needs a licence?
In Ontario, many trades require certification through Skilled Trades Ontario (STO). Plumbers working on regulated systems must hold the appropriate Certificate of Qualification. Always ask for their trade ID number and verify it directly.
- Certificate of Qualification (C of Q) from Skilled Trades Ontario
- WSIB coverage for workplace injury protection
- Minimum $2M general liability insurance
- Municipal business licence (requirements vary by city)
When is a building permit required?
Not every job needs a permit, but structural changes, major system modifications, and new installations typically do. Working without a required permit can result in fines, insurance issues, and problems when selling your home.
- New installations or system replacements often require permits
- Minor repairs and maintenance generally do not
- Your contractor should pull the permit — not you
- Permit costs vary by municipality ($50–$500+)
How to verify credentials
Never take a contractor's word for it. Ontario makes it easy to verify credentials online.
- Skilled Trades Ontario: verify Certificate of Qualification at skilledtradesontario.ca
- WSIB: check coverage status at wsib.ca
- ESA (electrical): verify at esasafe.com
- TSSA (gas/fuel): verify at tssa.org
- Municipal business licence: contact your local city clerk
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Browse PlumbersFrequently Asked Questions
Do all plumbers in Ontario need a licence?
Trades performing regulated work in Ontario must hold a Certificate of Qualification from Skilled Trades Ontario. Some specializations have additional requirements through bodies like the ESA or TSSA.
What happens if I hire an unlicensed contractor?
You may void your home insurance, face liability for injuries, and have no legal recourse for poor work. Unpermitted work can also create issues when selling your property.
Who is responsible for pulling the building permit?
Your contractor should pull all required permits and schedule inspections. If they ask you to pull the permit, that's a red flag — it may mean they're not licensed.