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Journeyman Plumber Exam practice questions

205 free questions with answers and explanations.

Practice test
  1. 101.A plumber is installing a battery of four lavatories in a public restroom. Each lavatory has a 1 1/4-inch trap and discharges into a 2-inch horizontal branch drain. What is the maximum developed length allowed for the trap arm of each lavatory to its vent connection according to common plumbing codes?Drainage, Waste, and Venting (DWV) Systems
  2. 102.A plumber is installing a gas clothes dryer in a residential laundry room. The dryer requires a flexible connector for connection to the rigid gas piping. Which of the following is an essential requirement for the installation of this flexible connector?Gas Piping
  3. 103.A plumber is installing a potable water heater in a residential garage. The local code requires a thermal expansion tank. What is the primary purpose of installing this tank?Water Supply Systems
  4. 104.A plumber is installing a battery of four commercial lavatories in a public restroom. Each lavatory is assigned 1 DFU. The branch drain serving these lavatories is 2 inches in diameter. What is the maximum developed length allowed for this 2-inch horizontal branch drain before it requires a separate vent or connection to a larger vent stack?Drainage, Waste, and Venting (DWV) Systems
  5. 105.A plumber is installing a new residential DWV system. The main building drain connects to the public sewer at the property line. What is the minimum size, in inches, required for a cleanout installed at the junction of the building drain and the building sewer?Drainage, Waste, and Venting (DWV) Systems
  6. 106.A plumber is troubleshooting a domestic hot water recirculation system in a large residential building. The system uses a dedicated return line and a recirculation pump. Residents on upper floors are complaining about long wait times for hot water, despite the pump running continuously. What is the most likely cause of this issue?Water Supply Systems
  7. 107.A plumber is designing a DWV system for a multi-story building. Which type of vent pipe extends vertically through the roof and serves as the primary vent for the entire drainage system?Drainage, Waste, and Venting (DWV) Systems
  8. 108.A plumber is installing a fixture trap for a clothes washer standpipe. What is the minimum trap arm diameter required for this installation?Drainage, Waste, and Venting (DWV) Systems
  9. 109.A plumber is installing a floor drain in a commercial kitchen. The drain is subject to heavy grease and oil discharge. Which of the following is REQUIRED to be installed upstream of this floor drain?Drainage, Waste, and Venting (DWV) Systems
  10. 110.A newly constructed multi-story commercial building requires a drainage system for its roof. What is the minimum required slope for a horizontal 6-inch roof drain leader that collects stormwater and discharges into the building storm sewer?Drainage, Waste, and Venting (DWV) Systems
  11. 111.A plumber is repairing a section of a 4-inch cast iron drainage pipe. The repair involves cutting out a damaged section and replacing it. What is the most common and acceptable method for joining new cast iron pipe to existing cast iron pipe in residential or commercial DWV systems today?Drainage, Waste, and Venting (DWV) Systems
  12. 112.A plumber is designing a potable water distribution system for a new three-story apartment building. The building will have a constant supply pressure of 60 PSI at the entry point. What is the approximate maximum height above the entry point that a fixture can be reliably supplied with water before considering additional pressure boosting, assuming a minimum residual pressure of 20 PSI is required at the fixture and accounting for typical friction losses?Water Supply Systems
  13. 113.A plumber is installing a water heater in a commercial building. The building's potable water supply is known to have high levels of sediment and particulate matter. Which type of water heater would generally be most susceptible to efficiency loss and damage from these conditions, requiring more frequent maintenance?Water Supply Systems
  14. 114.A plumber is installing a floor drain in a commercial kitchen. The drain is subject to heavy grease discharge. What type of interceptor is required to prevent grease from entering the building's drainage system?Drainage, Waste, and Venting (DWV) Systems
  15. 115.A plumber is installing a 2-inch drainage pipe in a residential bathroom. The pipe will serve a single lavatory and a shower. What is the maximum developed length allowed for the trap arm connecting the shower P-trap to its vent, assuming a 2-inch trap arm?Drainage, Waste, and Venting (DWV) Systems
  16. 116.A plumber is installing a gas-fired commercial boiler in a building. The boiler has an input rating of 1,200,000 BTUs per hour. The gas pressure at the meter is 2 psig. The total length of the gas piping run from the meter to the boiler is 120 feet, including equivalent lengths for fittings. Using a 1.0 inch water column pressure drop, what is the minimum nominal pipe size required for this installation, assuming Schedule 40 steel pipe?Gas Piping
  17. 117.A plumber is installing new water distribution piping in a commercial kitchen using Type K copper tubing. The local health department requires that all water lines exposed to potential chemical spills or physical damage in this area be protected. Which of the following methods would provide the most effective and code-compliant protection for the copper piping in such an environment?Water Supply Systems
  18. 118.A plumber is installing a water distribution system in a new commercial building. The design calls for a main cold water supply line to be sized based on a total fixture unit count of 450. Using the Hunter's Curve method for a system with 60 PSI available pressure at the meter and a desired minimum residual pressure of 20 PSI at the highest fixture, what is the approximate required meter and building supply pipe size?Water Supply Systems
  19. 119.A plumber is performing a final inspection of a newly installed gas piping system in a commercial building. Which of the following is NOT an acceptable material for gas piping within a building according to most plumbing codes?Gas Piping
  20. 120.A plumber is installing a water distribution system in a large custom home. The homeowner wants to ensure that hot water is available almost instantly at all fixtures, even those far from the water heater. Which of the following system components, when properly designed, is essential for achieving this goal efficiently?Water Supply Systems
  21. 121.A plumber is inspecting a newly installed DWV system before final cover. What is the minimum required test pressure for an air test on the drainage portion of the system?Drainage, Waste, and Venting (DWV) Systems
  22. 122.A plumber is installing a 3-inch horizontal drainage pipe. What is the maximum number of drainage fixture units (DFUs) this pipe can serve if it has a slope of 1/4 inch per foot?Drainage, Waste, and Venting (DWV) Systems
  23. 123.A plumber is sizing a common vent for two lavatories and one bathtub, all connected to the same branch. The lavatories each have a DFU of 1, and the bathtub has a DFU of 2. What is the minimum diameter for the common vent pipe if it serves these fixtures?Drainage, Waste, and Venting (DWV) Systems
  24. 124.A plumber is installing a fixture trap for a floor drain located in a commercial kitchen. What is the minimum trap seal depth typically required for this type of installation?Drainage, Waste, and Venting (DWV) Systems
  25. 125.A plumber is designing a DWV system for a new medical laboratory. The lab will generate corrosive chemical waste from several sinks. Which of the following pipe materials is most suitable for handling this type of waste?Drainage, Waste, and Venting (DWV) Systems
  26. 126.A plumber is inspecting a newly installed 4-inch building sewer. What is the minimum required size for the cleanout fitting that must be installed at the junction of the building drain and the building sewer?Drainage, Waste, and Venting (DWV) Systems
  27. 127.A plumber is installing a fixture trap for a commercial dishwasher in a restaurant. The dishwasher discharges indirectly into a floor sink. What is the minimum size for the trap arm connecting the floor sink to the drainage system?Drainage, Waste, and Venting (DWV) Systems
  28. 128.A plumber is installing a floor sink that receives discharge from a commercial ice machine. This discharge must not directly connect to the sanitary drainage system. What type of waste connection is required?Drainage, Waste, and Venting (DWV) Systems
  29. 129.A plumber is inspecting a newly installed 4-inch building sewer. What is the minimum required cleanout size for this pipe?Drainage, Waste, and Venting (DWV) Systems
  30. 130.A plumber is performing a mandatory annual test on a reduced pressure principle (RPZ) backflow prevention assembly. During the test, the differential pressure relief valve opens to atmosphere when the pressure downstream of the No. 1 check valve is reduced. What is the acceptable pressure difference (differential pressure) at which the relief valve should open, relative to the supply pressure, for the assembly to pass this test?Water Supply Systems
  31. 131.A plumber is installing a main vent stack for a 5-story commercial building. The building's main soil or waste stack is 4 inches in diameter. What is the minimum required diameter for the main vent stack?Drainage, Waste, and Venting (DWV) Systems
  32. 132.A plumber is installing a water distribution system in a new home using PEX tubing. The local code allows the use of PEX-a, PEX-b, and PEX-c. Which of the following statements accurately describes a key characteristic or application difference between these types of PEX tubing?Water Supply Systems
  33. 133.A plumber is inspecting a newly installed 4-inch building sewer. What is the maximum distance a cleanout can be from the junction of the building drain and the building sewer?Drainage, Waste, and Venting (DWV) Systems
  34. 134.A plumber is installing a new branch drain line connecting to a stack. According to most plumbing codes, what is the maximum developed length of a fixture drain for a water closet (toilet) before it must connect to a vent or a vented branch?Drainage, Waste, and Venting (DWV) Systems
  35. 135.A plumber is installing a water distribution system in a new home. The local code permits the use of PEX-A, PEX-B, and PEX-C tubing. Which type of PEX is typically manufactured using the Engel method (peroxide method) and is known for its highest degree of cross-linking and superior flexibility, even at low temperatures?Water Supply Systems
  36. 136.A plumber is sizing the water distribution piping for a residential dwelling. The dwelling has 2 bathrooms, a kitchen, and a laundry room. The total developed length of the main cold water line from the meter to the furthest fixture is 100 feet. The available street main pressure is 60 psi, and the desired minimum residual pressure at the highest fixture is 20 psi. The fixture unit count for the dwelling is 18. Using the Hunter's Curve method, what is the maximum allowable pressure loss due to friction for the entire cold water distribution system?Water Supply Systems
  37. 137.A plumber is designing a hot water recirculation system for a large custom home to ensure instant hot water at all fixtures. To maintain system efficiency and prevent short-cycling of the water heater, what type of valve is essential to install on the recirculation return line just before it reconnects to the water heater inlet?Water Supply Systems
  38. 138.A plumber is installing a new 4-inch building drain that will serve a total of 150 drainage fixture units (DFUs) and has a slope of 1/8 inch per foot. According to plumbing codes, what is the maximum permissible DFU load for this pipe?Drainage, Waste, and Venting (DWV) Systems
  39. 139.A plumber is performing a final pressure test on a newly installed water distribution system inside a commercial building. The system is designed for a maximum working pressure of 80 PSI. According to commonly adopted plumbing codes, what is the minimum test pressure the system should be subjected to for at least 30 minutes, without any leakage?Water Supply Systems
  40. 140.A plumber is installing a water service line from a municipal main to a new residential dwelling. The municipal water main pressure is consistently 80 PSI. The local plumbing code requires that the maximum static pressure within a domestic water distribution system not exceed 80 PSI. What device, if any, is required at the point of connection to the dwelling's water supply?Water Supply Systems
  41. 141.A plumber is installing a Category I natural draft furnace. What is the minimum required clearance from combustible materials for a single-wall metal vent connector, assuming no special protection is applied to the combustibles?Gas Piping
  42. 142.When installing a horizontal drainage pipe, what is the minimum required slope for a 3-inch (75 mm) pipe according to most plumbing codes?Drainage, Waste, and Venting (DWV) Systems
  43. 143.A plumber is installing a grease interceptor for a restaurant kitchen. Which of the following statements about grease interceptor installation is FALSE?Drainage, Waste, and Venting (DWV) Systems
  44. 144.A plumber is installing a new drainage system in a residential bathroom. The shower stall requires a 2-inch trap. What is the maximum developed length permitted for the trap arm connecting this shower trap to the horizontal branch drain?Drainage, Waste, and Venting (DWV) Systems
  45. 145.A plumber is designing a water distribution system for a medical clinic. The clinic requires a high level of water quality and consistent pressure for sensitive equipment. The design includes a water treatment system. Which component is crucial to prevent the treated water from flowing back into the municipal supply during a pressure drop in the main?Water Supply Systems
  46. 146.A plumber is sizing a hot water distribution system for a multi-family residential building. The design calls for a continuous supply of hot water to multiple fixtures simultaneously. Which of the following is a primary factor that influences the required flow rate (GPM) for sizing the hot water distribution piping?Water Supply Systems
  47. 147.A plumber is installing a fixture trap for a dishwasher that discharges into a standpipe. What is the maximum developed length from the trap weir to the vent fitting?Drainage, Waste, and Venting (DWV) Systems
  48. 148.A plumber is installing a new natural gas line to a residential clothes dryer. The dryer has an input rating of 22,000 BTUs per hour. The gas meter is located 40 feet from the dryer connection. Using standard pressure (0.5 psig) and 0.5 inches water column pressure drop, what is the minimum nominal pipe size required for this installation, assuming schedule 40 steel pipe?Gas Piping
  49. 149.A plumber is installing a water distribution system in an older building where renovation is taking place. The existing piping is galvanized steel, which needs to be connected to new copper piping. What is the most important fitting to use at the connection point between galvanized steel and copper piping to prevent accelerated corrosion?Water Supply Systems
  50. 150.A plumber is performing a mandatory annual test on a reduced pressure principle (RPZ) backflow prevention assembly. After closing the #2 shut-off valve and opening the #2 test cock, the differential pressure reading across the relief valve is 0 PSI. What does this reading indicate?Water Supply Systems