Master Plumber Exam Cheat Sheet 2026

The 30 highest-yield Master Plumber Exam facts, distilled from real exam questions. Print it, save it as a PDF, or study it here — free, no sign-up.

1. A relief vent is installed primarily to prevent which condition? → Pressure buildup in the stack that could unseal traps on lower floors
2. The IPC requires that vent pipes penetrating a roof extend a minimum of how far above the roof surface in areas subject to frost? → 12 inches
3. Which action is required when a plumber discovers existing work that violates the current plumbing code during a renovation project? → Report it to the AHJ immediately
4. Which pipe sizing approach accounts for velocity limits to prevent erosion and noise in copper water supply piping? → Velocity-based sizing limiting flow to 8 ft/s
5. Per the IPC, what is the minimum diameter of a stack vent or vent stack that serves a building drain handling more than 100 fixture units? → 4 inches
6. A suds pressure zone in a DWV stack results from which condition? → High fixture unit loading causing water to fill the entire stack cross-section
7. Under the IPC, which of the following fixtures requires a floor drain to be installed within a specific proximity under certain occupancy conditions? → Water heater relief valve discharge
8. A master plumber takes on an apprentice who performs work unsupervised and causes property damage. Who bears primary liability? → The master plumber who is responsible for supervision
9. A gas-fired water heater installed in a garage must be elevated so the ignition source is at least how high above the floor? → 18 inches
10. What does 'PN6' designation mean for PVC pressure pipes used in water supply systems in the Philippines? → Pressure Nominal rating of 6 bar (600 kPa)
11. Which of the following factors determines the license requirements: → Authority having jurisdiction
12. When is a Safety Data Sheet (SDS) required to be available on a jobsite? → At all times when hazardous chemicals are present
13. Under the IPC, a 3-inch horizontal drain serving a water closet must have a minimum slope of: → 1/4 inch per foot
14. In the Philippine Plumbing Code, what is the term for the pipe connecting a fixture trap to the vent system? → Trap arm
15. Which backflow prevention method provides the highest level of protection for a potable water supply? → Air gap
16. A double sanitary tee (double tee-wye) fitting is used when connecting back-to-back fixtures to permit flow in which directions simultaneously? → From both sides into a common vertical drop
17. When sizing a thermal expansion tank for a closed water heating system, which factor is most critical? → The system volume, temperature rise, and incoming cold water pressure
18. When is an 'island fixture vent' (Chicago loop) used? → When a fixture cannot be vented through the roof due to its location in a kitchen island
19. Under OSHA 29 CFR 1926, what is the minimum distance that a trench must be from a spoil pile to prevent cave-in hazards? → 2 feet
20. What is the minimum depth of cover required for a building sewer installed under a driveway? → 18 inches
21. Which sizing standard is used for gas piping design to ensure adequate BTU delivery to all appliances? → Longest-length method or branch-length method per NFPA 54/IPC
22. Which federal agency regulates lead content in plumbing materials used in public water systems under the Safe Drinking Water Act? → EPA
23. When calculating the total demand in WSFU (water supply fixture units) for a system, what accounts for demand diversity? → Using the probability curve that converts WSFU to gallons per minute
24. A plumber finds asbestos-containing pipe insulation in a commercial building. What is the CORRECT immediate action? → Stop work, secure the area, and notify a licensed asbestos abatement contractor
25. Per the IPC, what is the minimum slope required for a 3-inch horizontal drainage pipe? → 1/8 inch per foot
26. Which venting method allows multiple fixtures on a horizontal branch to share a single vent at the end of the branch? → Circuit venting
27. A gas appliance connector (flexible connector) used to connect a range to the gas supply line may be a maximum of: → 4 feet
28. What is the minimum required vent stack size when a drainage stack serves more than 10 branch intervals in a building? → One-half the diameter of the drainage stack it serves
29. A pressure-reducing valve (PRV) should be installed when the municipal supply pressure exceeds which threshold per the IPC? → 80 psi
30. Under OSHA standards, a ladder used on a construction site must be capable of supporting what multiple of the maximum intended load? → Four times