# Plumber (306A)

## Fast facts

| Trade code | 306A |
| --- | --- |
| Sector | Construction |
| Classification | Compulsory trade (O. Reg. 876/21, s. 2) |
| Certifying exam | Required (O. Reg. 876/21, s. 3) |
| Apprentice to journeyperson ratio | Subject to a ratio (O. Reg. 876/21, s. 4) |
| Red Seal trade | Yes |
| Active apprentices in Ontario | 3,337 (reported in Ontario's apprenticeship dataset) |
| Approved sponsors | 1,586 |
| Certifying body | Skilled Trades Ontario |

Last verified August 20, 2026 against the sources listed below.

## What does a plumber do?

A Plumber installs, repairs and maintains piping systems, fixtures and other plumbing equipment used for water distribution, drainage and waste disposal.

Skilled Trades Ontario describes the work of this trade as follows:

- lays out, assembles, installs, maintains and repairs piping, fixtures and other components for the supply or disposal of water for any domestic or industrial purpose
- connects any appliance that uses water
- installs the piping for any process, including the conveyance of gas, or any tubing for a pneumatic or air-handling system
- reads and understands design drawings, manufacturers’ literature, and installation diagrams for piping and appliances

## How long is the plumber apprenticeship?

| Total training hours | 9,000 (about 5 years) |
| --- | --- |
| On the job | 8,280 hours |
| In school | 720 hours |
| In-school levels | 3 |

These hours are set by the Registrar of Skilled Trades Ontario under section 14 of the Building Opportunities in the Skilled Trades Act, 2021.

## What do you study in school for the 306A?

The in-school portion covers, but is not limited to:

- workplace safety, rigging, and hoisting
- pipe and fitting materials, pipe supports and hangers
- tools and piping methods
- plumbing fixtures, appliances and equipment
- properties of water and heat transfer
- trade calculations, construction drawings and job specifications
- codes, regulations and standards
- drainage, venting and waste piping systems
- sewage disposal systems
- water distribution systems

## Is plumber a compulsory trade in Ontario?

Yes. Plumber is one of the 23 trades classified as compulsory by section 2 of O. Reg. 876/21 under the Building Opportunities in the Skilled Trades Act, 2021. To practice a compulsory trade legally in Ontario, a person must hold a Certificate of Qualification, a Provisional Certificate of Qualification, or a Registered Training Agreement, and their information appears on the [Skilled Trades Ontario Public Register](https://www.skilledtradesontario.ca/public-register/), where anyone can check whether a specific person is certified.

Working in this trade without one of those three documents is an offence, subject to limited exemptions such as approved pre-apprenticeship program participants. See the full [list of compulsory trades in Ontario](https://ontariocertificationregistry.ca/trades/compulsory/) for how this trade compares to the other 22.

## How do you become a plumber in Ontario?

The apprenticeship pathway for this trade is administered by Skilled Trades Ontario under section 14 of the Building Opportunities in the Skilled Trades Act, 2021:

1. **Find a sponsor and register a training agreement.** An employer or union sponsor takes you on and the training agreement is registered with the ministry. For this trade the Registered Training Agreement is also your legal authorization to work while you train.
2. **Complete the on the job and in school training.** The skills are set out in the trade's Apprenticeship Training Standard, signed off by your sponsor as you demonstrate them, alongside levels of in school theory at a training delivery agent.
3. **Receive your Certificate of Apprenticeship.** Skilled Trades Ontario issues it when the program is complete.
4. **Pass the certifying exam.** This trade has a certifying exam under O. Reg. 876/21, s. 3. Passing it earns the Certificate of Qualification, which compulsory trade workers must then hold and renew to keep practicing.

The exact training standard, current curriculum and program details are on the [Skilled Trades Ontario page for Plumber](https://www.skilledtradesontario.ca/trade-information/plumber/). On the job hour requirements vary by trade and are not published on this page yet; confirm them in the training standard before signing an agreement.

## Is there an apprentice to journeyperson ratio for the 306A?

Yes. Plumber is one of the 33 trades that section 4 of O. Reg. 876/21 makes subject to an apprentice to journeyperson ratio. The regulation establishes that a ratio applies, but the numeric ratio itself is not stated in section 4. Confirm the current ratio with Skilled Trades Ontario before registering an additional apprentice, because it limits how many apprentices a sponsor may train at once.

## Is the 306A a Red Seal trade?

Yes. Plumber participates in the Interprovincial Red Seal Program, the national standard for the trade across Canada, stewarded by the Canadian Council of Directors of Apprenticeship. A Red Seal endorsement on an Ontario Certificate of Qualification means the qualification is recognized in other provinces and territories without re examination, which matters for workers moving between provinces and for employers hiring from outside Ontario.

The Red Seal exam for this trade has 125 multiple-choice questions, each with four possible answers and exactly one correct answer.

### How the 125 questions are distributed

| Major Work Activity | Questions |
| --- | --- |
| A. Performs common occupational skills | 14 |
| B. Prepares and assembles tube, tubing and pipe | 13 |
| C. Installs, tests and services sewers, sewage treatment systems and drainage, waste and vent (DWV) systems | 32 |
| D. Installs, tests and services water service and distribution | 24 |
| E. Installs, tests and services fixtures, appliances and water treatment systems | 17 |
| F. Installs, tests and services low-pressure steam and hydronic systems | 16 |
| G. Installs, tests and services specialized systems | 9 |

By question type, this trade's exam runs 15 to 25% knowledge and recall, 60 to 70% procedural and application, and 10 to 20% critical thinking.

- [Red Seal exam breakdown for Plumber: question counts by task](https://red-seal.ca/eng/trades/plumbers/exam-information.shtml)
- [Red Seal exam preparation checklist](https://red-seal.ca/eng/resources/preparation-checklist.shtml)
- [How to register for a Red Seal exam](https://red-seal.ca/eng/resources/register.shtml)

## How often does the certificate need to be renewed?

Journeypersons in compulsory trades must renew their Certificate of Qualification every year, per [Skilled Trades Ontario](https://www.skilledtradesontario.ca/about-trades/work-in-the-compulsory-trades/). A lapsed certificate in a compulsory trade means the holder is no longer legally entitled to practice the trade until it is restored, so the renewal date is worth tracking ahead of time. The current renewal fee is not published on this page yet; confirm it with Skilled Trades Ontario.

## Already experienced? The Trade Equivalency Assessment

Workers with experience from outside Ontario's apprenticeship system, or from another country, can apply for a Trade Equivalency Assessment instead of starting an apprenticeship. Approval requires verifiable evidence of competency in the trade's Training Standard and experience at least equal to the trade's total training time; if approved, you challenge the certifying exam directly. The assessment costs $235 plus HST, and a reassessment with new evidence costs $100 plus HST, per [Skilled Trades Ontario's Trade Equivalency Assessment page](https://www.skilledtradesontario.ca/experienced-workers/trade-equivalency-assessment/).

## Certification is not the only paperwork

A Certificate of Qualification covers the person. Running a business in the trade carries its own obligations: many Ontario municipalities require a contractor licence on top of personal certification, and construction employers must complete WSIB registration before work begins. Both are indexed on our sister site: [municipal contractor licensing requirements by city](https://ontariotraderegistry.ca/licensing/) and [WSIB Form 1000, registration of constructors and employers](https://ontariotraderegistry.ca/compliance/wsib-form-1000/), on Ontario Trade Registry.

For wages, demand and what the day-to-day work looks like, see the [Plumber career profile](https://bluecraneworks.ca/plumber-306a-certification.html) on Blue Crane Works.

## What does a plumber earn in Ontario?

| Median wage | $32.50 per hour |
| --- | --- |
| Low | $20.00 |
| High | $50.38 |
| Occupation measured | Plumbers (NOC 72300) |
| Reference period | 2023-2024 |

Published by Employment and Social Development Canada through Job Bank, for Ontario as a whole. Read it as the pay range for the occupational group this trade belongs to, not a guaranteed rate: one NOC code can cover more than one trade, and wages vary by region, employer and experience.

## Is the 306A recognised outside Ontario?

This trade has been part of the Interprovincial Red Seal Program since 1958. 13 of Canada's 13 provinces and territories designate it Red Seal: AB, BC, MB, NB, NL, NS, NT, NU, ON, PE, QC, SK, YT, Ontario among them. Its National Occupational Classification code is 72300, which is how federal labour market data refers to this occupation.

## Where can you train as a plumber in Ontario?

| Public training providers | 12 colleges deliver the in-school portion |
| --- | --- |
| Private training providers | 1 |
| Approved sponsors | 1,586 employers registered to train apprentices |
| Apprentices in training | 3,337 |

Counts are from Ontario's published apprenticeships dataset. A sponsor is the employer or union that registers and trains the apprentice; you need one before an apprenticeship can start.

## How dangerous is construction work in Ontario?

Ontario does not publish injury figures per trade, only by sector. In 2024 the Ministry of Labour recorded 18 worker fatalities and 442 critical injuries under the construction health and safety program. See [the ten-year counts and what they leave out](https://ontariocertificationregistry.ca/trades/safety/).

## Related Ontario trades

Other construction sector trades with certification records on this registry:

- [Concrete Pump Operator (637C) certification requirements](https://ontariocertificationregistry.ca/trades/637c-concrete-pump-operator/)
- [Drywall Finisher and Plasterer (453A) certification requirements](https://ontariocertificationregistry.ca/trades/453a-drywall-finisher-and-plasterer/)
- [Electrician - Construction and Maintenance (309A) certification requirements](https://ontariocertificationregistry.ca/trades/309a-electrician-construction-and-maintenance/)
- [Heat and Frost Insulator (253A) certification requirements](https://ontariocertificationregistry.ca/trades/253a-heat-and-frost-insulator/)
- [Heavy Equipment Operator - Dozer (636C) certification requirements](https://ontariocertificationregistry.ca/trades/636c-heavy-equipment-operator-dozer/)
- [G2 Gas Technician 2 fuel certificate requirements](https://ontariocertificationregistry.ca/certificates/g2-gas-technician/)
- [All 23 compulsory trades in Ontario](https://ontariocertificationregistry.ca/trades/compulsory/)

## Official verification sources

- Regulation[O. Reg. 876/21, Prescribed Trades and Related Matters (e-Laws)](https://www.ontario.ca/laws/regulation/210876)
- Certifying body[Skilled Trades Ontario: Plumber](https://www.skilledtradesontario.ca/trade-information/plumber/)
- Act[Building Opportunities in the Skilled Trades Act, 2021 (e-Laws)](https://www.ontario.ca/laws/statute/21b28)
- Wages[Job Bank wage data, Employment and Social Development Canada](https://open.canada.ca/data/en/dataset/adad580f-76b0-4502-bd05-20c125de9116)
- Red Seal profile[red-seal.ca: Plumber trade profile](https://red-seal.ca/eng/trades/plumber.shtml)
- Participation data[Ontario open data: Apprenticeships dataset](https://data.ontario.ca/dataset/apprenticeships)Classification, exam requirement and ratio status on this page are read directly from O. Reg. 876/21 as consolidated on e-Laws, not from secondary summaries. Facts not yet verified against a primary source are marked as not published rather than estimated.

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Source: https://ontariocertificationregistry.ca/trades/306a-plumber/