Journeyman Plumber Licensing Exam
Questions and Correct Answers Verified
Answers) Plus Rationales 2026 Q&A |
Instant Download Pdf
1. What is the minimum slope 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
Answer: B. 1/4 inch per foot
Rationale: Most plumbing codes require 1/4 inch per foot slope for pipes
2½ inches or smaller, and this is commonly applied to 3-inch lines for
proper drainage.
2. What does DWV stand for?
A. Drain Waste Vent
B. Direct Water Valve
,C. Drain Water Volume
D. Domestic Waste Vent
Answer: A. Drain Waste Vent
Rationale: DWV systems handle drainage, waste removal, and venting
of plumbing systems.
3. Which material is most commonly used for residential water supply
piping?
A. Cast iron
B. PVC
C. Copper
D. Galvanized steel
Answer: C. Copper
Rationale: Copper is widely used due to durability, corrosion resistance,
and reliability.
4. What is the purpose of a plumbing vent?
A. Increase water pressure
B. Remove waste
,C. Allow air into the system
D. Filter water
Answer: C. Allow air into the system
Rationale: Vents equalize pressure and prevent siphoning of traps.
5. What is the minimum trap seal depth?
A. 1 inch
B. 2 inches
C. 3 inches
D. 4 inches
Answer: B. 2 inches
Rationale: Plumbing codes generally require a minimum 2-inch trap seal
to prevent sewer gas entry.
6. Which pipe is used for venting only?
A. ABS
B. PVC
C. Copper
D. All of the above
, Answer: D. All of the above
Rationale: Various materials can be used for venting depending on code
approval.
7. What is the function of a P-trap?
A. Increase flow
B. Prevent backflow
C. Hold water to block gases
D. Filter debris
Answer: C. Hold water to block gases
Rationale: The water seal prevents sewer gases from entering buildings.
8. What is the maximum distance a trap arm can run without a vent
(typical)?
A. 2 feet
B. 4 feet
C. 6 feet
D. 8 feet
Questions and Correct Answers Verified
Answers) Plus Rationales 2026 Q&A |
Instant Download Pdf
1. What is the minimum slope 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
Answer: B. 1/4 inch per foot
Rationale: Most plumbing codes require 1/4 inch per foot slope for pipes
2½ inches or smaller, and this is commonly applied to 3-inch lines for
proper drainage.
2. What does DWV stand for?
A. Drain Waste Vent
B. Direct Water Valve
,C. Drain Water Volume
D. Domestic Waste Vent
Answer: A. Drain Waste Vent
Rationale: DWV systems handle drainage, waste removal, and venting
of plumbing systems.
3. Which material is most commonly used for residential water supply
piping?
A. Cast iron
B. PVC
C. Copper
D. Galvanized steel
Answer: C. Copper
Rationale: Copper is widely used due to durability, corrosion resistance,
and reliability.
4. What is the purpose of a plumbing vent?
A. Increase water pressure
B. Remove waste
,C. Allow air into the system
D. Filter water
Answer: C. Allow air into the system
Rationale: Vents equalize pressure and prevent siphoning of traps.
5. What is the minimum trap seal depth?
A. 1 inch
B. 2 inches
C. 3 inches
D. 4 inches
Answer: B. 2 inches
Rationale: Plumbing codes generally require a minimum 2-inch trap seal
to prevent sewer gas entry.
6. Which pipe is used for venting only?
A. ABS
B. PVC
C. Copper
D. All of the above
, Answer: D. All of the above
Rationale: Various materials can be used for venting depending on code
approval.
7. What is the function of a P-trap?
A. Increase flow
B. Prevent backflow
C. Hold water to block gases
D. Filter debris
Answer: C. Hold water to block gases
Rationale: The water seal prevents sewer gases from entering buildings.
8. What is the maximum distance a trap arm can run without a vent
(typical)?
A. 2 feet
B. 4 feet
C. 6 feet
D. 8 feet
