Alabama Journeyman Plumber Exam Verified
Questions, Correct Answers, and Detailed
Explanations for Science Students||Already
Graded A+
1. Which type of pipe is most commonly used for residential water
supply lines?
A. Cast iron
B. Copper
C. Clay
D. Galvanized steel
Answer: B. Copper
Copper is durable, corrosion-resistant, and approved by most
plumbing codes for potable water.
2. What is the minimum slope 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. No slope required
Answer: B. 1/4 inch per foot
Code requires at least 1/4 inch per foot to ensure proper drainage
and prevent blockages.
3. Which fitting is used to change the direction of flow by 90
degrees?
,A. Tee
B. Coupling
C. Elbow
D. Union
Answer: C. Elbow
Elbows are designed specifically to change pipe direction.
4. What is the primary purpose of a plumbing vent?
A. Increase water pressure
B. Prevent leaks
C. Allow air into the drainage system
D. Remove wastewater
Answer: C. Allow air into the drainage system
Vents prevent siphoning of traps and allow proper drainage flow.
5. Which material is prohibited for potable water supply?
A. Copper
B. PEX
C. CPVC
D. Lead
Answer: D. Lead
Lead is unsafe for drinking water and banned by plumbing codes.
6. What device prevents contaminated water from flowing back
into the potable system?
A. Pressure regulator
B. Backflow preventer
,C. Air chamber
D. Trap
Answer: B. Backflow preventer
This device protects the water supply from cross-contamination.
7. What is the standard water closet rough-in distance from the
finished wall?
A. 10 inches
B. 12 inches
C. 14 inches
D. 16 inches
Answer: B. 12 inches
Most residential toilets are designed for a 12-inch rough-in.
8. Which pipe is best suited for underground sewer lines?
A. Copper
B. Galvanized steel
C. PVC Schedule 40
D. PEX
Answer: C. PVC Schedule 40
PVC is corrosion-resistant and approved for underground drainage.
9. What is the function of a P-trap?
A. Increase water flow
B. Prevent sewer gases from entering a building
C. Reduce water pressure
D. Filter debris
, Answer: B. Prevent sewer gases from entering a building
The water seal in a P-trap blocks sewer gases.
10. What tool is used to cut threaded pipe?
A. Tubing cutter
B. Hacksaw
C. Pipe cutter
D. Grinder
Answer: C. Pipe cutter
Pipe cutters provide clean, square cuts needed for threading.
11. Which fitting allows for easy disconnection of pipes?
A. Elbow
B. Tee
C. Union
D. Coupling
Answer: C. Union
Unions allow pipes to be disconnected without cutting.
12. What is the minimum size vent pipe for a single bathroom
group?
A. 1 inch
B. 1½ inches
C. 2 inches
D. 3 inches
Answer: B. 1½ inches
This size meets minimum code requirements for proper venting.
Questions, Correct Answers, and Detailed
Explanations for Science Students||Already
Graded A+
1. Which type of pipe is most commonly used for residential water
supply lines?
A. Cast iron
B. Copper
C. Clay
D. Galvanized steel
Answer: B. Copper
Copper is durable, corrosion-resistant, and approved by most
plumbing codes for potable water.
2. What is the minimum slope 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. No slope required
Answer: B. 1/4 inch per foot
Code requires at least 1/4 inch per foot to ensure proper drainage
and prevent blockages.
3. Which fitting is used to change the direction of flow by 90
degrees?
,A. Tee
B. Coupling
C. Elbow
D. Union
Answer: C. Elbow
Elbows are designed specifically to change pipe direction.
4. What is the primary purpose of a plumbing vent?
A. Increase water pressure
B. Prevent leaks
C. Allow air into the drainage system
D. Remove wastewater
Answer: C. Allow air into the drainage system
Vents prevent siphoning of traps and allow proper drainage flow.
5. Which material is prohibited for potable water supply?
A. Copper
B. PEX
C. CPVC
D. Lead
Answer: D. Lead
Lead is unsafe for drinking water and banned by plumbing codes.
6. What device prevents contaminated water from flowing back
into the potable system?
A. Pressure regulator
B. Backflow preventer
,C. Air chamber
D. Trap
Answer: B. Backflow preventer
This device protects the water supply from cross-contamination.
7. What is the standard water closet rough-in distance from the
finished wall?
A. 10 inches
B. 12 inches
C. 14 inches
D. 16 inches
Answer: B. 12 inches
Most residential toilets are designed for a 12-inch rough-in.
8. Which pipe is best suited for underground sewer lines?
A. Copper
B. Galvanized steel
C. PVC Schedule 40
D. PEX
Answer: C. PVC Schedule 40
PVC is corrosion-resistant and approved for underground drainage.
9. What is the function of a P-trap?
A. Increase water flow
B. Prevent sewer gases from entering a building
C. Reduce water pressure
D. Filter debris
, Answer: B. Prevent sewer gases from entering a building
The water seal in a P-trap blocks sewer gases.
10. What tool is used to cut threaded pipe?
A. Tubing cutter
B. Hacksaw
C. Pipe cutter
D. Grinder
Answer: C. Pipe cutter
Pipe cutters provide clean, square cuts needed for threading.
11. Which fitting allows for easy disconnection of pipes?
A. Elbow
B. Tee
C. Union
D. Coupling
Answer: C. Union
Unions allow pipes to be disconnected without cutting.
12. What is the minimum size vent pipe for a single bathroom
group?
A. 1 inch
B. 1½ inches
C. 2 inches
D. 3 inches
Answer: B. 1½ inches
This size meets minimum code requirements for proper venting.
