ALABAMA 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. Filter potable water
Correct answer: B. Prevent sewer gases from entering a
building
Rationale: A trap maintains a water seal that prevents sewer
gases and odors from entering occupied spaces.
2. Which component is primarily used to protect potable
water from backflow?
A. Cleanout
B. Trap
C. Backflow preventer
D. Drain strainer
Correct answer: C. Backflow preventer
Rationale: Backflow-prevention devices protect the potable-
water supply from contamination caused by reverse flow.
,3. What does DWV stand for?
A. Drain, Water, Valve
B. Drain, Waste, Vent
C. Domestic Water Valve
D. Drain Water Volume
Correct answer: B. Drain, Waste, Vent
Rationale: DWV systems remove wastewater and provide
venting so drainage systems operate properly.
4. What is the main function of a plumbing vent?
A. Supply hot water
B. Increase water temperature
C. Protect trap seals and allow proper drainage-system airflow
D. Remove sediment from water
Correct answer: C. Protect trap seals and allow proper
drainage-system airflow
Rationale: Venting balances pressures within the drainage
system and helps prevent trap siphonage or backpressure.
5. Which pipe material is commonly used for potable cold-
water distribution?
A. PVC
B. Cast iron soil pipe
,C. ABS DWV pipe only
D. Clay sewer pipe
Correct answer: A. PVC
Rationale: Approved PVC pressure pipe can be used for
potable-water distribution when it is listed and installed for
that application.
6. What is the purpose of a cleanout?
A. Increase water pressure
B. Provide access for cleaning a drainage pipe
C. Reduce pipe diameter
D. Prevent thermal expansion
Correct answer: B. Provide access for cleaning a drainage pipe
Rationale: Cleanouts provide access to drainage piping for
inspection, rodding, and maintenance.
7. Which condition can cause a trap to lose its water seal
through siphonage?
A. Excessive negative pressure in the drainage system
B. Proper venting
C. Low water temperature
D. Large water heater
Correct answer: A. Excessive negative pressure in the drainage
system
, Rationale: Negative pressure can pull water from a trap unless
the drainage system is properly vented.
8. What is the purpose of a shutoff valve on a plumbing
fixture?
A. Increase drain flow
B. Allow the fixture's water supply to be isolated
C. Vent the drainage system
D. Prevent sewer gases
Correct answer: B. Allow the fixture's water supply to be
isolated
Rationale: Fixture shutoff valves allow maintenance or
replacement without shutting down the entire building water
system.
9. Which fitting is normally used to change the direction of a
pipe run?
A. Coupling
B. Elbow
C. Union
D. Cap
Correct answer: B. Elbow
Rationale: Elbows are designed to change the direction of
piping.
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. Filter potable water
Correct answer: B. Prevent sewer gases from entering a
building
Rationale: A trap maintains a water seal that prevents sewer
gases and odors from entering occupied spaces.
2. Which component is primarily used to protect potable
water from backflow?
A. Cleanout
B. Trap
C. Backflow preventer
D. Drain strainer
Correct answer: C. Backflow preventer
Rationale: Backflow-prevention devices protect the potable-
water supply from contamination caused by reverse flow.
,3. What does DWV stand for?
A. Drain, Water, Valve
B. Drain, Waste, Vent
C. Domestic Water Valve
D. Drain Water Volume
Correct answer: B. Drain, Waste, Vent
Rationale: DWV systems remove wastewater and provide
venting so drainage systems operate properly.
4. What is the main function of a plumbing vent?
A. Supply hot water
B. Increase water temperature
C. Protect trap seals and allow proper drainage-system airflow
D. Remove sediment from water
Correct answer: C. Protect trap seals and allow proper
drainage-system airflow
Rationale: Venting balances pressures within the drainage
system and helps prevent trap siphonage or backpressure.
5. Which pipe material is commonly used for potable cold-
water distribution?
A. PVC
B. Cast iron soil pipe
,C. ABS DWV pipe only
D. Clay sewer pipe
Correct answer: A. PVC
Rationale: Approved PVC pressure pipe can be used for
potable-water distribution when it is listed and installed for
that application.
6. What is the purpose of a cleanout?
A. Increase water pressure
B. Provide access for cleaning a drainage pipe
C. Reduce pipe diameter
D. Prevent thermal expansion
Correct answer: B. Provide access for cleaning a drainage pipe
Rationale: Cleanouts provide access to drainage piping for
inspection, rodding, and maintenance.
7. Which condition can cause a trap to lose its water seal
through siphonage?
A. Excessive negative pressure in the drainage system
B. Proper venting
C. Low water temperature
D. Large water heater
Correct answer: A. Excessive negative pressure in the drainage
system
, Rationale: Negative pressure can pull water from a trap unless
the drainage system is properly vented.
8. What is the purpose of a shutoff valve on a plumbing
fixture?
A. Increase drain flow
B. Allow the fixture's water supply to be isolated
C. Vent the drainage system
D. Prevent sewer gases
Correct answer: B. Allow the fixture's water supply to be
isolated
Rationale: Fixture shutoff valves allow maintenance or
replacement without shutting down the entire building water
system.
9. Which fitting is normally used to change the direction of a
pipe run?
A. Coupling
B. Elbow
C. Union
D. Cap
Correct answer: B. Elbow
Rationale: Elbows are designed to change the direction of
piping.
