LOUISIANA JOURNEYMAN PLUMBER EXAM
QUESTIONS AND CORRECT ANSWERS (VERIFIED
ANSWERS) Q&A 2027 |INSTANT DOWNLOAD PDF
1. What is the primary purpose of a plumbing trap?
A. Increase water pressure
B. Prevent sewer gases from entering a building
C. Increase drainage velocity
D. Reduce pipe diameter
Correct Answer: B. Prevent sewer gases from entering a
building
Rationale: A trap maintains a water seal that blocks sewer
gases from entering occupied spaces.
2. Which fitting is commonly used to change the direction of a
drainage pipe by 90 degrees?
A. Coupling
B. Union
C. Elbow
D. Reducer
Correct Answer: C. Elbow
Rationale: An elbow changes the direction of piping while
maintaining the flow path.
3. What is the main function of a cleanout?
A. Increase water temperature
,B. Provide access for cleaning drainage piping
C. Prevent backflow
D. Reduce water pressure
Correct Answer: B. Provide access for cleaning drainage piping
Rationale: Cleanouts provide accessible openings for removing
blockages and servicing drainage piping.
4. Which pipe is commonly used for potable cold-water
distribution?
A. PVC
B. ABS drain pipe
C. Cast-iron soil pipe
D. Clay sewer pipe
Correct Answer: A. PVC
Rationale: Approved PVC water pipe can be used for potable-
water distribution where permitted by the applicable code.
5. What does DWV stand for?
A. Drain, Water, Valve
B. Drainage, Waste, and Vent
C. Domestic Water Valve
D. Drainage Water Volume
Correct Answer: B. Drainage, Waste, and Vent
Rationale: DWV systems collect wastewater and provide
venting to protect drainage flow and trap seals.
6. What is the purpose of a plumbing vent?
A. Supply drinking water
,B. Increase fixture temperature
C. Protect trap seals and allow proper drainage flow
D. Reduce pipe strength
Correct Answer: C. Protect trap seals and allow proper
drainage flow
Rationale: Venting equalizes pressure in the drainage system
and helps prevent trap siphonage or backpressure.
7. Which device prevents contaminated water from flowing
backward into the potable water supply?
A. Cleanout
B. Backflow preventer
C. Water heater
D. Expansion tank
Correct Answer: B. Backflow preventer
Rationale: Backflow-prevention devices protect potable water
from contamination caused by reverse flow.
8. What is the purpose of a water shutoff valve?
A. Vent a drainage system
B. Control or stop water flow
C. Increase pipe diameter
D. Remove sewer gases
Correct Answer: B. Control or stop water flow
Rationale: Shutoff valves isolate fixtures, branches, or portions
of a plumbing system.
, 9. Which tool is commonly used to cut copper tubing?
A. Tubing cutter
B. Pipe wrench
C. Drain snake
D. Basin wrench
Correct Answer: A. Tubing cutter
Rationale: A tubing cutter makes a controlled, generally square
cut on copper tubing.
10. What should be done to copper tubing before making a
soldered joint?
A. Paint the tubing
B. Clean the mating surfaces
C. Fill the tubing with water
D. Thread the tubing
Correct Answer: B. Clean the mating surfaces
Rationale: Clean surfaces allow flux and solder to form a
reliable joint.
11. What is flux used for in soldering copper pipe?
A. Increase pipe thickness
B. Clean and prepare metal surfaces for soldering
C. Seal threaded joints permanently
D. Lubricate drain cables
Correct Answer: B. Clean and prepare metal surfaces for
soldering
QUESTIONS AND CORRECT ANSWERS (VERIFIED
ANSWERS) Q&A 2027 |INSTANT DOWNLOAD PDF
1. What is the primary purpose of a plumbing trap?
A. Increase water pressure
B. Prevent sewer gases from entering a building
C. Increase drainage velocity
D. Reduce pipe diameter
Correct Answer: B. Prevent sewer gases from entering a
building
Rationale: A trap maintains a water seal that blocks sewer
gases from entering occupied spaces.
2. Which fitting is commonly used to change the direction of a
drainage pipe by 90 degrees?
A. Coupling
B. Union
C. Elbow
D. Reducer
Correct Answer: C. Elbow
Rationale: An elbow changes the direction of piping while
maintaining the flow path.
3. What is the main function of a cleanout?
A. Increase water temperature
,B. Provide access for cleaning drainage piping
C. Prevent backflow
D. Reduce water pressure
Correct Answer: B. Provide access for cleaning drainage piping
Rationale: Cleanouts provide accessible openings for removing
blockages and servicing drainage piping.
4. Which pipe is commonly used for potable cold-water
distribution?
A. PVC
B. ABS drain pipe
C. Cast-iron soil pipe
D. Clay sewer pipe
Correct Answer: A. PVC
Rationale: Approved PVC water pipe can be used for potable-
water distribution where permitted by the applicable code.
5. What does DWV stand for?
A. Drain, Water, Valve
B. Drainage, Waste, and Vent
C. Domestic Water Valve
D. Drainage Water Volume
Correct Answer: B. Drainage, Waste, and Vent
Rationale: DWV systems collect wastewater and provide
venting to protect drainage flow and trap seals.
6. What is the purpose of a plumbing vent?
A. Supply drinking water
,B. Increase fixture temperature
C. Protect trap seals and allow proper drainage flow
D. Reduce pipe strength
Correct Answer: C. Protect trap seals and allow proper
drainage flow
Rationale: Venting equalizes pressure in the drainage system
and helps prevent trap siphonage or backpressure.
7. Which device prevents contaminated water from flowing
backward into the potable water supply?
A. Cleanout
B. Backflow preventer
C. Water heater
D. Expansion tank
Correct Answer: B. Backflow preventer
Rationale: Backflow-prevention devices protect potable water
from contamination caused by reverse flow.
8. What is the purpose of a water shutoff valve?
A. Vent a drainage system
B. Control or stop water flow
C. Increase pipe diameter
D. Remove sewer gases
Correct Answer: B. Control or stop water flow
Rationale: Shutoff valves isolate fixtures, branches, or portions
of a plumbing system.
, 9. Which tool is commonly used to cut copper tubing?
A. Tubing cutter
B. Pipe wrench
C. Drain snake
D. Basin wrench
Correct Answer: A. Tubing cutter
Rationale: A tubing cutter makes a controlled, generally square
cut on copper tubing.
10. What should be done to copper tubing before making a
soldered joint?
A. Paint the tubing
B. Clean the mating surfaces
C. Fill the tubing with water
D. Thread the tubing
Correct Answer: B. Clean the mating surfaces
Rationale: Clean surfaces allow flux and solder to form a
reliable joint.
11. What is flux used for in soldering copper pipe?
A. Increase pipe thickness
B. Clean and prepare metal surfaces for soldering
C. Seal threaded joints permanently
D. Lubricate drain cables
Correct Answer: B. Clean and prepare metal surfaces for
soldering
