IPC Cheat Sheet 2026

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

1. Which of the following trap designs is expressly prohibited by the International Plumbing Code because it relies on moving parts to maintain its seal? → A trap with a float ball mechanism
2. When connecting a dry vent pipe to a horizontal sanitary drainage pipe, which of the following describes the required connection point? → At or above the centerline of the horizontal drain
3. According to the IPC, what happens to the trap seal when a nearby fixture discharges a large volume of water rapidly? → Induced siphonage can pull the trap seal out
4. Under the IPC, what protection is required where drainage piping passes under a building foundation? → A sleeve or casing two pipe sizes larger must be used
5. Under the IPC, when is an oil separator required on a drainage system? → When flammable liquids or oils may be discharged into the system
6. Which of the following is an unacceptable location for a potable water service pipe according to the IPC? → Located in, under, or above a septic tank drainage field.
7. Gray water that enters a collection reservoir must be ________. → Filtered
8. A plumber is installing fixtures in a new commercial building. Which of the following is a requirement for water closets provided for public use? → They must be equipped with seats of the hinged open-front type.
9. Per the IPC, what is required at the joint between a roof drain body and a structural concrete deck? → A clamping ring that secures waterproofing membrane to the drain body
10. According to the IPC, 'clear-water waste' drainage systems handle discharge from sources such as: → Non-contaminated sources such as air conditioning condensate and swimming pool backwash
11. What does the IPC specify regarding the use of used or reclaimed plumbing materials? → They may be used if approved by the code official
12. A plumber is installing a new building sewer. According to the IPC, a cleanout is required at intervals of not more than: → 100 feet
13. Under the IPC, when is a laundry interceptor required? → In commercial laundry facilities that may discharge lint, string, or rags
14. Flux can only be used in the brazing process when: → Brazing copper to brass
15. Under the IPC, what type of trap is specifically prohibited for use in drainage systems? → S-trap
16. When flow controls are installed on gas piping, they __________. → Are used to keep operating pressure lower than the supply pressure
17. What is the maximum amount of time that gray water is allowed to be retained for use to flush a toilet or urinal? → 72 hours
18. Flexible water connections are required to be _________. → accessible
19. Per the IPC, what is the maximum spacing allowed between cleanouts on a building storm drain? → 100 feet
20. According to the IPC, what is the minimum distance a vent opening must be from any operable window or air intake? → 10 feet
21. All pipes used in plumbing applications will have all of the following markings except: → Length of pipe
22. Which of the following is NOT typically a power or duty of the code official as defined in Chapter 1 of the IPC? → To establish the fee schedule for permits and inspections.
23. Per the IPC, the design rainfall intensity used for sizing storm drainage systems must be based on: → Rainfall data specific to the geographical location of the project
24. Water heaters, hose bibs and sill cocks are normally protected from backflow with ________. → A vacuum breaker
25. What does the IPC require regarding the grade of underground horizontal drainage piping? → A uniform grade throughout the entire run
26. Under the IPC, what is the minimum frequency for cleaning a hydromechanical grease interceptor? → When it reaches 25% grease capacity
27. Under the IPC, what type of valve is required on the water supply to each individual plumbing fixture? → An accessible shutoff valve
28. According to the IPC, what is required for plumbing installations in seismic design categories D, E, and F? → Piping must be braced and supported for seismic forces
29. What does the IPC require regarding the testing of backflow prevention assemblies after installation? → They must be tested immediately after installation and annually thereafter
30. In a commercial building, the static water pressure from the city main is found to be 95 psi. What action is required by the IPC? → Install a pressure-reducing valve to reduce the pressure to 80 psi or less.