6 realistic IPC questions for the US master plumber exam, written for the IPC 2024 edition. Click to reveal the answer and explanation. Free practice starts with the first chapter of every exam in the app.
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These 6 sample questions represent the type of questions you will encounter on the US Master Plumber exam — set from the International Plumbing Code (IPC), with both the knowledge and calculations sections testing your ability to find and apply code rules, not to memorize them.
Click the Show Answer button under each question to see the correct answer and a detailed explanation. Use these questions to practice your code-navigation skills — chapter map, section numbering, and the index — and to identify areas that need more study.
MasterPlumberPractice covers the six markets it serves — Georgia, Colorado, Oklahoma, Utah, Vermont and New Hampshire — each with its own guide. Sign up for free to start with the first chapter of each exam part in your state.
What is the minimum slope for a horizontal drainage pipe 3 inches or smaller?
✅ Correct Answer: 1/4 inch per foot
IPC Table 704.1 requires 1/4 inch per foot for pipes 3 inches and smaller; 4 inches and larger may use 1/8 inch per foot.
Reference: IPC 704.1 · Table 704.1
What is the required water seal depth for a plumbing trap?
✅ Correct Answer: 2 to 4 inches
Every trap must have a liquid seal of not less than 2 inches and not more than 4 inches to block sewer gas.
Reference: IPC 1002.2
A vent terminal through a roof must extend at least how far above the roof?
✅ Correct Answer: 6 inches
Vent terminals must extend at least 6 inches above the roof, measured from the highest point of penetration.
Reference: IPC 905.4
Where must the T&P relief valve discharge pipe terminate?
✅ Correct Answer: 6 to 24 inches above the floor
The discharge pipe must terminate 6 to 24 inches above the floor with no threads and no shutoff valve.
Reference: IPC 504.6
A dwelling bathroom group (lavatory, water closet, tub/shower) adds approximately how many water supply fixture units?
✅ Correct Answer: 6 WSFU
A private bathroom group counts as about 6 water supply fixture units under the IPC fixture unit tables.
Reference: IPC 604.3 · Table E103.3(1)
A cleanout is required at the base of a soil stack and within what distance of the building sewer connection?
✅ Correct Answer: 10 feet
Cleanouts are required at the base of each stack and within 10 feet of the building sewer connection on the building drain.
Reference: IPC 707.2
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Yes. All six IPC practice questions on this page are free to read and answer, with no account and no payment. Each one shows the code section it tests and a short explanation, so you can check your reasoning against the IPC 2024 before you decide whether to register.
They are written for the US master plumber license exam — the two scored parts taken against the International Plumbing Code (IPC): code knowledge and calculations. MasterPlumberPractice prepares candidates for the six markets it serves: Georgia, Colorado, Oklahoma, Utah, Vermont and New Hampshire.
The IPC 2024 edition. Every question cites the section it tests — for example IPC 704.1 for drainage slope, IPC 1002.2 for trap seal depth and IPC 905.4 for vent terminals — so you practise the code-navigation habit the exam rewards.
The full platform covers the complete blueprint of your state: IPC-style practice questions across both exam parts, full code theory, timed simulations in the format your board publishes and an AI tutor. You can start free with the first chapter of each exam part before paying anything.