Journeyman Plumber Licensing Exam
With Actual Questions & Verified
Answers, Plus Explained
Rationales/Expert Verified For
Guaranteed Pass 2026/Latest
Updated/Instant Download Pdf
1. What is the minimum slope for a horizontal drainage pipe to
ensure proper flow?
A) 1/8 inch per foot
B) 1/4 inch per foot
C) 1/2 inch per foot
D) 1 inch per foot
B) 1/4 inch per foot
Rationale: A horizontal drainage pipe should have a minimum slope of
1/4 inch per foot to ensure proper gravity flow of wastewater.
2. Which material is commonly used for potable water supply lines?
A) PVC
B) CPVC
C) ABS
D) Galvanized steel
B) CPVC
Rationale: CPVC (Chlorinated Polyvinyl Chloride) is approved for
,potable water and can withstand hot water temperatures, unlike
standard PVC.
3. What is the purpose of a vent in a plumbing system?
A) To supply water
B) To remove wastewater
C) To prevent siphoning of traps
D) To increase water pressure
C) To prevent siphoning of traps
Rationale: Vents allow air into the plumbing system, preventing
siphoning of water traps and allowing proper drainage.
4. How many inches above the floor should a water closet (toilet)
rim be for a standard installation?
A) 12 inches
B) 15 inches
C) 17 inches
D) 20 inches
C) 17 inches
Rationale: Standard toilet rim height is typically 15–19 inches above
the finished floor, with 17 inches being common for comfort and code
compliance.
5. What type of valve is commonly used to isolate water supply to a
fixture?
A) Ball valve
B) Check valve
C) Gate valve
D) Pressure-reducing valve
A) Ball valve
Rationale: Ball valves are commonly used to isolate water to
,individual fixtures because they provide full shutoff and are easy to
operate.
6. What is the primary purpose of a trap in plumbing?
A) To increase water pressure
B) To prevent sewer gases from entering a building
C) To regulate flow rate
D) To filter debris
B) To prevent sewer gases from entering a building
Rationale: Traps hold a small amount of water that acts as a barrier
to prevent sewer gases from entering the building.
7. Which pipe material is most resistant to corrosion in water supply
systems?
A) Copper
B) Galvanized steel
C) Cast iron
D) PVC
A) Copper
Rationale: Copper is highly resistant to corrosion and is widely used
for potable water supply systems.
8. What is the maximum distance a water closet can be from its
vent?
A) 2 feet
B) 4 feet
C) 6 feet
D) 10 feet
C) 6 feet
Rationale: Most plumbing codes specify a maximum distance of 6 feet
, from a water closet trap to its vent to maintain proper trap seal and
venting.
9. Which type of fitting is used to change the direction of a pipe by
90 degrees?
A) Tee
B) Elbow
C) Coupling
D) Reducer
B) Elbow
Rationale: An elbow fitting is used to change the direction of a pipe,
commonly available in 45° and 90° angles.
10. What is the primary function of a backflow preventer?
A) Increase water pressure
B) Stop water contamination from reverse flow
C) Filter sediment
D) Reduce water velocity
B) Stop water contamination from reverse flow
Rationale: Backflow preventers protect potable water systems from
contamination caused by reverse flow or siphoning.
11. Which of the following is a proper method for joining copper
pipes?
A) Solvent welding
B) Threaded connection
C) Soldering
D) Gluing
C) Soldering
Rationale: Soldering (sweating) is a standard method to join copper
pipes, ensuring a leak-free joint.
With Actual Questions & Verified
Answers, Plus Explained
Rationales/Expert Verified For
Guaranteed Pass 2026/Latest
Updated/Instant Download Pdf
1. What is the minimum slope for a horizontal drainage pipe to
ensure proper flow?
A) 1/8 inch per foot
B) 1/4 inch per foot
C) 1/2 inch per foot
D) 1 inch per foot
B) 1/4 inch per foot
Rationale: A horizontal drainage pipe should have a minimum slope of
1/4 inch per foot to ensure proper gravity flow of wastewater.
2. Which material is commonly used for potable water supply lines?
A) PVC
B) CPVC
C) ABS
D) Galvanized steel
B) CPVC
Rationale: CPVC (Chlorinated Polyvinyl Chloride) is approved for
,potable water and can withstand hot water temperatures, unlike
standard PVC.
3. What is the purpose of a vent in a plumbing system?
A) To supply water
B) To remove wastewater
C) To prevent siphoning of traps
D) To increase water pressure
C) To prevent siphoning of traps
Rationale: Vents allow air into the plumbing system, preventing
siphoning of water traps and allowing proper drainage.
4. How many inches above the floor should a water closet (toilet)
rim be for a standard installation?
A) 12 inches
B) 15 inches
C) 17 inches
D) 20 inches
C) 17 inches
Rationale: Standard toilet rim height is typically 15–19 inches above
the finished floor, with 17 inches being common for comfort and code
compliance.
5. What type of valve is commonly used to isolate water supply to a
fixture?
A) Ball valve
B) Check valve
C) Gate valve
D) Pressure-reducing valve
A) Ball valve
Rationale: Ball valves are commonly used to isolate water to
,individual fixtures because they provide full shutoff and are easy to
operate.
6. What is the primary purpose of a trap in plumbing?
A) To increase water pressure
B) To prevent sewer gases from entering a building
C) To regulate flow rate
D) To filter debris
B) To prevent sewer gases from entering a building
Rationale: Traps hold a small amount of water that acts as a barrier
to prevent sewer gases from entering the building.
7. Which pipe material is most resistant to corrosion in water supply
systems?
A) Copper
B) Galvanized steel
C) Cast iron
D) PVC
A) Copper
Rationale: Copper is highly resistant to corrosion and is widely used
for potable water supply systems.
8. What is the maximum distance a water closet can be from its
vent?
A) 2 feet
B) 4 feet
C) 6 feet
D) 10 feet
C) 6 feet
Rationale: Most plumbing codes specify a maximum distance of 6 feet
, from a water closet trap to its vent to maintain proper trap seal and
venting.
9. Which type of fitting is used to change the direction of a pipe by
90 degrees?
A) Tee
B) Elbow
C) Coupling
D) Reducer
B) Elbow
Rationale: An elbow fitting is used to change the direction of a pipe,
commonly available in 45° and 90° angles.
10. What is the primary function of a backflow preventer?
A) Increase water pressure
B) Stop water contamination from reverse flow
C) Filter sediment
D) Reduce water velocity
B) Stop water contamination from reverse flow
Rationale: Backflow preventers protect potable water systems from
contamination caused by reverse flow or siphoning.
11. Which of the following is a proper method for joining copper
pipes?
A) Solvent welding
B) Threaded connection
C) Soldering
D) Gluing
C) Soldering
Rationale: Soldering (sweating) is a standard method to join copper
pipes, ensuring a leak-free joint.
