New Jersey Master Plumber Exam Questions
And Correct Answers (Verified Answers) Plus
Rationales 2026 Q&A | Instant Download Pdf
1. What is the minimum slope required for a 2-inch horizontal
drainage pipe?
A) 1/16 inch per foot
B) 1/8 inch per foot
C) 1/4 inch per foot
D) 1/2 inch per foot
C) 1/4 inch per foot
This slope ensures proper gravity flow and prevents clogging.
2. Which of the following materials is approved for underground
potable water service in New Jersey?
A) PVC Schedule 40
B) Copper Type M
C) PEX
D) Galvanized Steel
B) Copper Type M
Copper Type M is approved for underground potable water
installations due to its durability and corrosion resistance.
3. The primary purpose of a vent in a plumbing system is to:
A) Prevent sewer gas from entering the building
B) Increase water pressure
C) Filter debris from water
D) Reduce water temperature
A) Prevent sewer gas from entering the building
, Vents allow air to enter the drainage system, preventing siphoning
and the escape of gases.
4. What is the maximum distance a water closet trap can be from the
vent?
A) 2 feet
B) 3 feet
C) 5 feet
D) 6 feet
D) 6 feet
According to plumbing codes, the maximum distance ensures
proper venting and prevents trap seal loss.
5. What is the minimum size for a residential water service pipe?
A) 1/2 inch
B) 3/4 inch
C) 1 inch
D) 1 1/4 inch
B) 3/4 inch
3/4 inch is the minimum size to provide adequate flow and
pressure for typical residential use.
6. Which valve is recommended for isolating a water heater for
maintenance?
A) Gate Valve
B) Globe Valve
C) Ball Valve
D) Check Valve
C) Ball Valve
, Ball valves provide full shutoff with a simple quarter-turn
operation, ideal for water heaters.
7. The maximum distance between supports for horizontal 1-inch
copper tubing is:
A) 2 feet
B) 3 feet
C) 4 feet
D) 5 feet
C) 4 feet
Proper support prevents sagging and stress on joints.
8. Which type of pipe joint is commonly used for cast iron soil pipes?
A) Threaded
B) Hub and spigot with lead and oakum
C) Solvent cement
D) Compression fitting
B) Hub and spigot with lead and oakum
This traditional method ensures a watertight, durable joint.
9. A P-trap is designed to:
A) Increase water velocity
B) Prevent odors from sewer gases
C) Provide additional water storage
D) Reduce water pressure
B) Prevent odors from sewer gases
The water held in the trap acts as a seal against sewer gas.
10. Which of the following is required for water heater
temperature and pressure relief?
A) Expansion tank
And Correct Answers (Verified Answers) Plus
Rationales 2026 Q&A | Instant Download Pdf
1. What is the minimum slope required for a 2-inch horizontal
drainage pipe?
A) 1/16 inch per foot
B) 1/8 inch per foot
C) 1/4 inch per foot
D) 1/2 inch per foot
C) 1/4 inch per foot
This slope ensures proper gravity flow and prevents clogging.
2. Which of the following materials is approved for underground
potable water service in New Jersey?
A) PVC Schedule 40
B) Copper Type M
C) PEX
D) Galvanized Steel
B) Copper Type M
Copper Type M is approved for underground potable water
installations due to its durability and corrosion resistance.
3. The primary purpose of a vent in a plumbing system is to:
A) Prevent sewer gas from entering the building
B) Increase water pressure
C) Filter debris from water
D) Reduce water temperature
A) Prevent sewer gas from entering the building
, Vents allow air to enter the drainage system, preventing siphoning
and the escape of gases.
4. What is the maximum distance a water closet trap can be from the
vent?
A) 2 feet
B) 3 feet
C) 5 feet
D) 6 feet
D) 6 feet
According to plumbing codes, the maximum distance ensures
proper venting and prevents trap seal loss.
5. What is the minimum size for a residential water service pipe?
A) 1/2 inch
B) 3/4 inch
C) 1 inch
D) 1 1/4 inch
B) 3/4 inch
3/4 inch is the minimum size to provide adequate flow and
pressure for typical residential use.
6. Which valve is recommended for isolating a water heater for
maintenance?
A) Gate Valve
B) Globe Valve
C) Ball Valve
D) Check Valve
C) Ball Valve
, Ball valves provide full shutoff with a simple quarter-turn
operation, ideal for water heaters.
7. The maximum distance between supports for horizontal 1-inch
copper tubing is:
A) 2 feet
B) 3 feet
C) 4 feet
D) 5 feet
C) 4 feet
Proper support prevents sagging and stress on joints.
8. Which type of pipe joint is commonly used for cast iron soil pipes?
A) Threaded
B) Hub and spigot with lead and oakum
C) Solvent cement
D) Compression fitting
B) Hub and spigot with lead and oakum
This traditional method ensures a watertight, durable joint.
9. A P-trap is designed to:
A) Increase water velocity
B) Prevent odors from sewer gases
C) Provide additional water storage
D) Reduce water pressure
B) Prevent odors from sewer gases
The water held in the trap acts as a seal against sewer gas.
10. Which of the following is required for water heater
temperature and pressure relief?
A) Expansion tank
