Journeyman Plumber Licensing Exam
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. Prevent sewer gases from entering the building
C. Improve drainage speed
D. Store water for reuse
Answer: B
Rationale: Traps hold water to create a seal that blocks sewer gases.
2. What is the minimum slope for a horizontal drainage pipe (≤3
inches)?
A. 1/16 inch per foot
B. 1/8 inch per foot
C. 1/4 inch per foot
,D. 1/2 inch per foot
Answer: C
Rationale: Standard code requires 1/4 inch per foot slope for proper
drainage.
3. Which pipe material is commonly used for DWV systems?
A. Copper
B. PVC
C. Steel
D. Brass
Answer: B
Rationale: PVC is widely used for Drain, Waste, and Vent systems.
4. What does DWV stand for?
A. Drain Water Valve
B. Domestic Water Vent
C. Drain Waste Vent
D. Direct Water Volume
Answer: C
Rationale: DWV refers to Drain, Waste, and Vent systems.
,5. What is the function of a vent pipe?
A. Supply water
B. Remove wastewater
C. Equalize pressure in the drainage system
D. Heat water
Answer: C
Rationale: Vent pipes prevent vacuum and allow proper drainage.
6. What type of valve is used to prevent backflow?
A. Gate valve
B. Ball valve
C. Check valve
D. Globe valve
Answer: C
Rationale: Check valves allow flow in one direction only.
7. What is the standard water pressure range for residential
plumbing?
, A. 10–20 psi
B. 20–40 psi
C. 40–80 psi
D. 80–120 psi
Answer: C
Rationale: Ideal residential pressure is between 40–80 psi.
8. What is the purpose of a cleanout?
A. Increase flow rate
B. Access pipes for cleaning
C. Prevent leaks
D. Reduce pressure
Answer: B
Rationale: Cleanouts allow maintenance access to drainage systems.
9. Which fitting is used to change pipe direction by 90°?
A. Tee
B. Elbow
C. Coupling
D. Union
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. Prevent sewer gases from entering the building
C. Improve drainage speed
D. Store water for reuse
Answer: B
Rationale: Traps hold water to create a seal that blocks sewer gases.
2. What is the minimum slope for a horizontal drainage pipe (≤3
inches)?
A. 1/16 inch per foot
B. 1/8 inch per foot
C. 1/4 inch per foot
,D. 1/2 inch per foot
Answer: C
Rationale: Standard code requires 1/4 inch per foot slope for proper
drainage.
3. Which pipe material is commonly used for DWV systems?
A. Copper
B. PVC
C. Steel
D. Brass
Answer: B
Rationale: PVC is widely used for Drain, Waste, and Vent systems.
4. What does DWV stand for?
A. Drain Water Valve
B. Domestic Water Vent
C. Drain Waste Vent
D. Direct Water Volume
Answer: C
Rationale: DWV refers to Drain, Waste, and Vent systems.
,5. What is the function of a vent pipe?
A. Supply water
B. Remove wastewater
C. Equalize pressure in the drainage system
D. Heat water
Answer: C
Rationale: Vent pipes prevent vacuum and allow proper drainage.
6. What type of valve is used to prevent backflow?
A. Gate valve
B. Ball valve
C. Check valve
D. Globe valve
Answer: C
Rationale: Check valves allow flow in one direction only.
7. What is the standard water pressure range for residential
plumbing?
, A. 10–20 psi
B. 20–40 psi
C. 40–80 psi
D. 80–120 psi
Answer: C
Rationale: Ideal residential pressure is between 40–80 psi.
8. What is the purpose of a cleanout?
A. Increase flow rate
B. Access pipes for cleaning
C. Prevent leaks
D. Reduce pressure
Answer: B
Rationale: Cleanouts allow maintenance access to drainage systems.
9. Which fitting is used to change pipe direction by 90°?
A. Tee
B. Elbow
C. Coupling
D. Union
