The exam at a glance
- 125multiple-choice questions
- 70%pass mark (88 of 125 correct)
- 4 hourswriting time
- ~1.9 minper question on average
Every question has four options and one correct answer. There are no trick questions, and every question is worth one mark. A formula sheet and an acronym list are provided at the sitting.
Question types: knowledge and recall 15–25%, procedural and application 60–70%, critical thinking 10–20%.
What's on the exam
The questions follow the Plumber Red Seal Occupational Standard, grouped into major work activities. The biggest blocks are Installs, tests and services sewers, sewage treatment systems and DWV systems (32), Installs, tests and services water service and distribution (24), Installs, tests and services fixtures, appliances and water treatment systems (17).
| Block | Major work activity | Questions | Share |
|---|---|---|---|
| A | Performs common occupational skills | 14 | 11% |
| B | Prepares and assembles tube, tubing and pipe | 13 | 10% |
| C | Installs, tests and services sewers, sewage treatment systems and DWV systems | 32 | 26% |
| D | Installs, tests and services water service and distribution | 24 | 19% |
| E | Installs, tests and services fixtures, appliances and water treatment systems | 17 | 14% |
| F | Installs, tests and services low-pressure steam and hydronic systems | 16 | 13% |
| G | Installs, tests and services specialized systems | 9 | 7% |
| Total | 125 | 100% |
How to study
- Drainage, waste and vent (C, 32) is the biggest block. Know fixture units, trap and vent sizing, grades and cleanout rules.
- Water distribution (D, 24): pressure limits, pipe sizing, backflow prevention types and where each one is required.
- Practise the formula-sheet math: grade, offsets, expansion, pressure head and the hydronic BTU formula.
- The exam uses the National Plumbing Code. Learn how it is laid out so you can reason about a rule without your own book.
- Do the free self-assessment on the official exam page and spend your time on the tasks you rated lowest, weighted by how many questions they carry.
- Practise every day in short sets. When you get one wrong, work out why each wrong option is wrong, not just which one is right.
Try 3 sample questions
These are original practice questions from our Plumber question bank, not real exam questions.
Question 1 · Sewers
A building sewer is laid at a 2% grade. How much does it drop over a 15 m run?
- A. 150 mm
- B. 300 mm
- C. 30 mm
- D. 600 mm
Show the answer
B. 300 mm
2% means 2 units of drop per 100 units of run. 15 000 mm × 0.02 = 300 mm.
Question 2 · Water service
Static water pressure at a house is 690 kPa (100 psi). What does the National Plumbing Code call for?
- A. Nothing, as long as the pipe is rated for that pressure
- B. A bigger water meter to handle the extra flow
- C. A larger water service to bring the pressure down
- D. A pressure-reducing valve, since it's over 550 kPa
Show the answer
D. A pressure-reducing valve, since it's over 550 kPa
The NPC requires a PRV where static pressure can go over 550 kPa. High pressure is hard on fixtures, valves and water heaters.
Question 3 · Hydronic piping
In a closed hydronic system, where should the circulator be in relation to the expansion tank?
- A. Pumping toward the expansion tank
- B. Pumping away from the expansion tank
- C. Anywhere; it makes no difference
- D. On the return to the tank, right next to it
Show the answer
B. Pumping away from the expansion tank
The expansion tank connection is the point of no pressure change. A circulator pumping away from it adds pressure to the system, which helps get rid of air and prevents cavitation.
Every question in every trade is free for everyone until Dec 1. No sign-up needed.
Try 10 questions free, no account needed. Every question has a plain-language explanation.
Start practisingSources
- Red Seal Program: Plumber exam information (number of questions, breakdown, question types)
- Red Seal Exam Preparation Guide (70% pass mark, four-hour writing time, format)
- SkilledTradesBC: What to expect on exam day (four-hour time limit, materials provided)
Checked October 2026. Exam details can change, so confirm with the official page and your provincial or territorial apprenticeship authority before you write. RedSkillTrade is an independent study tool and isn't affiliated with the Red Seal Program.
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