Alabama Journeyman Plumber Exam
Practice Questions And Correct Answers
(Verified Answers) Plus Rationales 2026
Q&A | Instant Download Pdf
1. What is the primary purpose of a plumbing trap?
A. Increase water pressure
B. Filter sediment from water
C. Prevent sewer gases from entering the building
D. Improve drainage speed
Rationale: A plumbing trap maintains a water seal that blocks harmful
sewer gases from entering occupied spaces while allowing wastewater to
flow through the drainage system.
2. Which type of fitting is commonly used to change the direction of a
drainage pipe by 90 degrees?
A. Coupling
B. Reducer
,C. Union
D. Long-turn elbow
Rationale: Long-turn elbows are preferred in drainage systems because
they reduce flow resistance and minimize the chance of clogging.
3. What is the minimum slope generally required for a 3-inch horizontal
drainage pipe?
A. 1/8 inch per foot
B. 1/4 inch per foot
C. 1/2 inch per foot
D. 1 inch per foot
Rationale: A slope of 1/4 inch per foot generally provides sufficient gravity
flow while minimizing solids accumulation in typical drainage systems.
4. Which plumbing system is designed to carry wastewater without
human waste?
A. Soil system
B. Storm system
C. Waste system
D. Vent system
,Rationale: Waste systems carry wastewater from sinks, showers, and
similar fixtures, while soil systems carry waste containing human
excrement.
5. What is the primary function of a plumbing vent?
A. Increase water pressure
B. Heat the drainage system
C. Equalize air pressure within the drainage system
D. Filter wastewater
Rationale: Venting maintains atmospheric pressure in the drainage system,
allowing fixtures to drain properly without siphoning trap seals.
6. Which material is commonly used for residential drain, waste, and
vent piping?
A. Galvanized steel
B. Brass
C. PVC
D. Black steel
Rationale: PVC is lightweight, corrosion-resistant, and widely approved for
residential DWV installations.
7. Which tool is primarily used to cut copper tubing cleanly?
, A. Pipe wrench
B. Hacksaw
C. Tubing cutter
D. Adjustable wrench
Rationale: Tubing cutters produce square, burr-minimized cuts that are
ideal for soldered or brazed copper joints.
8. Before soldering copper pipe, the surfaces should be:
A. Painted
B. Lubricated
C. Cleaned and fluxed
D. Covered with tape
Rationale: Cleaning removes oxidation, while flux promotes proper solder
flow and strong leak-free joints.
9. Which valve is typically installed near a water meter to isolate the
building water supply?
A. Globe valve
B. Check valve
C. Main shutoff valve
D. Relief valve
Practice Questions And Correct Answers
(Verified Answers) Plus Rationales 2026
Q&A | Instant Download Pdf
1. What is the primary purpose of a plumbing trap?
A. Increase water pressure
B. Filter sediment from water
C. Prevent sewer gases from entering the building
D. Improve drainage speed
Rationale: A plumbing trap maintains a water seal that blocks harmful
sewer gases from entering occupied spaces while allowing wastewater to
flow through the drainage system.
2. Which type of fitting is commonly used to change the direction of a
drainage pipe by 90 degrees?
A. Coupling
B. Reducer
,C. Union
D. Long-turn elbow
Rationale: Long-turn elbows are preferred in drainage systems because
they reduce flow resistance and minimize the chance of clogging.
3. What is the minimum slope generally required for a 3-inch horizontal
drainage pipe?
A. 1/8 inch per foot
B. 1/4 inch per foot
C. 1/2 inch per foot
D. 1 inch per foot
Rationale: A slope of 1/4 inch per foot generally provides sufficient gravity
flow while minimizing solids accumulation in typical drainage systems.
4. Which plumbing system is designed to carry wastewater without
human waste?
A. Soil system
B. Storm system
C. Waste system
D. Vent system
,Rationale: Waste systems carry wastewater from sinks, showers, and
similar fixtures, while soil systems carry waste containing human
excrement.
5. What is the primary function of a plumbing vent?
A. Increase water pressure
B. Heat the drainage system
C. Equalize air pressure within the drainage system
D. Filter wastewater
Rationale: Venting maintains atmospheric pressure in the drainage system,
allowing fixtures to drain properly without siphoning trap seals.
6. Which material is commonly used for residential drain, waste, and
vent piping?
A. Galvanized steel
B. Brass
C. PVC
D. Black steel
Rationale: PVC is lightweight, corrosion-resistant, and widely approved for
residential DWV installations.
7. Which tool is primarily used to cut copper tubing cleanly?
, A. Pipe wrench
B. Hacksaw
C. Tubing cutter
D. Adjustable wrench
Rationale: Tubing cutters produce square, burr-minimized cuts that are
ideal for soldered or brazed copper joints.
8. Before soldering copper pipe, the surfaces should be:
A. Painted
B. Lubricated
C. Cleaned and fluxed
D. Covered with tape
Rationale: Cleaning removes oxidation, while flux promotes proper solder
flow and strong leak-free joints.
9. Which valve is typically installed near a water meter to isolate the
building water supply?
A. Globe valve
B. Check valve
C. Main shutoff valve
D. Relief valve
