Journeyman Plumbers Exam Cheat Sheet 2026

The 30 highest-yield Journeyman Plumbers Exam 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 is the correct mathematical constant used to calculate the 'travel' piece when the 'set' of a 60-degree offset is known? → 1.155
2. Which of the following is an illegal and prohibited type of trap in a modern DWV system? → S-trap
3. What is the minimum diameter of the discharge pipe for a T&P relief valve on a residential storage water heater? → 3/4 inch
4. Which of the following locations is strictly prohibited for the installation of gas piping according to the International Fuel Gas Code? → Through a circulating air duct or chimney.
5. Cleanouts are required in a drainage system to allow for access. For a horizontal drainage pipe that is 100 feet long, where must cleanouts be located? → At the upper terminal and for each 100 feet, or fraction thereof, of developed length.
6. Based on the Uniform Plumbing Code (UPC), what is the maximum allowable developed length of the trap arm for a 1 1/2-inch P-trap? → 5 feet
7. According to the International Plumbing Code (IPC) and Uniform Plumbing Code (UPC), what is the acceptable range for a fixture trap's water seal depth? → 2 inches to 4 inches
8. What is the minimum required diameter of a drain line from a water heater drain pan per most US plumbing codes? → 3/4 inch
9. A journeyman plumber is planning a horizontal DWV (Drainage, Waste, and Vent) line using 4-inch diameter pipe. What is the minimum required slope for this pipe? → 1/8 inch per foot
10. What is the minimum horizontal clearance required between a power vent water heater exhaust termination cap and a window or door opening? → 4 feet
11. When installing a flexible gas appliance connector for a residential gas range, what is the maximum permitted length according to most standards? → 6 feet (1.8 m)
12. In a multi-story building, how does an increase in elevation affect the available water pressure at the fixtures on the upper floors? → Pressure decreases by approximately 0.433 psi for every foot of elevation gain.
13. A plumber is connecting a lavatory drain to the p-trap. The component that connects the fixture's drain outlet to the trap is known as a: → Tailpiece
14. What is the purpose of a thermostatic mixing valve (tempering valve) installed at the outlet of a water heater? → To blend hot and cold water to deliver a safe, preset mixed temperature
15. When installing a lavatory to meet ADA accessibility standards, which of the following requirements for the pipes under the sink is correct? → Pipes must be insulated or configured to protect against contact.
16. Which of the following places wouldn't be a good place for an indirect waste receptor? → Both Closets and Unvented areas
17. Which of the following locations is explicitly prohibited for the installation of a gas shutoff valve according to most model fuel gas codes? → Within a furnace plenum or concealed location
18. Plans that have been approved must be stored on a job site and made available to code inspectors upon request. → TRUE
19. What is the primary energy advantage of a tankless (on-demand) water heater compared to a conventional storage water heater? → Elimination of standby heat loss
20. Which type of water heater venting uses a concentric pipe system to draw combustion air from outside while exhausting combustion gases directly outdoors? → Direct vent (sealed combustion)
21. In which seismic design categories are water heaters typically required to be anchored or strapped to prevent overturning during an earthquake? → Seismic Design Categories C, D, E, and F (high seismic risk areas)
22. What is required when a water heater is installed in an area subject to flooding or where the unit could be submerged? → The heater must be elevated above the base flood elevation
23. Trusses can't be _______________. → All of the above
24. What is the greatest possible separation between an accessible toilet faucet and the front edge of the toilet? → 25 inches
25. According to most plumbing codes, what is the maximum vertical distance allowed for a fixture tailpiece, measured from the fixture outlet to the trap weir? → 24 inches
26. According to most model plumbing codes, what is the minimum height a vent pipe must terminate above a roof surface? → 6 inches
27. What is the primary purpose of the sacrificial anode rod in a tank-type water heater? → To protect the steel tank lining from corrosion through galvanic action
28. According to most plumbing codes, what is the required range for a fixture trap's liquid seal depth? → 2 inches to 4 inches
29. What is the federally mandated maximum flow rate for a standard showerhead manufactured after 1994, according to the Energy Policy Act? → 2.5 GPM at 80 psi
30. According to most plumbing codes, what is the maximum allowable distance between cleanouts on a 4-inch horizontal drainage line? → 100 feet