Texas Journeyman Plumber Examination
(Verified Answers) Plus Rationales
2025/2026 Q&A | Instant Download Pdf
1. What is the minimum water pressure required at the plumbing fixtures in a
residential building?
A) 10 psi
B) 15 psi
C) 20 psi
D) 25 psi
Water pressure must be at least 20 psi at the fixtures to ensure proper
operation of plumbing appliances and prevent inadequate flow.
2. What type of pipe is commonly used for residential water supply lines?
A) Cast iron
B) Copper
C) Asbestos
D) Galvanized steel
Copper piping is widely used due to its durability, corrosion resistance, and ease
of installation.
3. What is the purpose of a P-trap in a plumbing system?
A) Increase water pressure
B) Filter debris
C) Prevent sewer gases from entering the building
D) Reduce water temperature
A P-trap creates a water seal that blocks sewer gases while allowing
wastewater to flow.
4. What is the maximum allowable length of a horizontal branch drain before
a cleanout is required?
A) 10 feet
B) 20 feet
C) 50 feet
D) 100 feet
,Horizontal drains longer than 50 feet require a cleanout for maintenance and
to prevent blockages.
5. In plumbing, what does “DWV” stand for?
A) Direct Water Valve
B) Drain, Waste, and Vent
C) Double Water Volume
D) Drainage With Vacuum
DWV systems handle drainage and venting of wastewater, not potable water
supply.
6. What is the minimum slope for a 3-inch horizontal drain pipe?
A) 1/8 inch per foot
B) 1/4 inch per foot
C) 1/8 to 1/4 inch per foot
D) 1/2 inch per foot
The slope ensures proper drainage by gravity without causing blockages.
7. Which type of valve is used to stop water flow completely?
A) Check valve
B) Gate valve
C) Ball valve
D) Pressure-reducing valve
Ball valves provide a full shutoff and are reliable for controlling water flow.
8. What is the minimum vent size for a single fixture?
A) 1 inch
B) 1.25 inches
C) 1.5 inches
D) 2 inches
The vent allows sewer gases to escape and ensures proper drainage; 1.5 inches
is the minimum standard for a single fixture.
9. What is the maximum distance a water closet can be from its vent?
A) 2 feet
B) 4 feet
C) 6 feet
, D) 8 feet
Venting distance limits prevent siphoning of traps and ensure proper airflow.
10. What is the purpose of a backflow preventer?
A) Increase water pressure
B) Prevent contaminated water from flowing back into the potable supply
C) Filter sediment
D) Reduce water temperature
Backflow preventers protect the public water supply from contamination.
11. What is the minimum distance a water heater must be installed from a
gas-fired appliance?
A) 6 inches
B) 12 inches
C) 18 inches
D) 24 inches
Maintaining clearance prevents heat damage and ensures safe operation.
12. What is the maximum temperature allowed for domestic hot water at the
fixture?
A) 110°F
B) 120°F
C) 125°F
D) 140°F
This prevents scalding while providing sufficient hot water for use.
13. Which of the following is a common material for sanitary sewer piping?
A) Copper
B) PVC
C) Aluminum
D) PEX
PVC is durable, lightweight, and corrosion-resistant, making it ideal for sanitary
sewer systems.
14. How many plumbing fixtures are allowed on a 1.5-inch branch drain?
A) 1
B) 2
C) 3
(Verified Answers) Plus Rationales
2025/2026 Q&A | Instant Download Pdf
1. What is the minimum water pressure required at the plumbing fixtures in a
residential building?
A) 10 psi
B) 15 psi
C) 20 psi
D) 25 psi
Water pressure must be at least 20 psi at the fixtures to ensure proper
operation of plumbing appliances and prevent inadequate flow.
2. What type of pipe is commonly used for residential water supply lines?
A) Cast iron
B) Copper
C) Asbestos
D) Galvanized steel
Copper piping is widely used due to its durability, corrosion resistance, and ease
of installation.
3. What is the purpose of a P-trap in a plumbing system?
A) Increase water pressure
B) Filter debris
C) Prevent sewer gases from entering the building
D) Reduce water temperature
A P-trap creates a water seal that blocks sewer gases while allowing
wastewater to flow.
4. What is the maximum allowable length of a horizontal branch drain before
a cleanout is required?
A) 10 feet
B) 20 feet
C) 50 feet
D) 100 feet
,Horizontal drains longer than 50 feet require a cleanout for maintenance and
to prevent blockages.
5. In plumbing, what does “DWV” stand for?
A) Direct Water Valve
B) Drain, Waste, and Vent
C) Double Water Volume
D) Drainage With Vacuum
DWV systems handle drainage and venting of wastewater, not potable water
supply.
6. What is the minimum slope for a 3-inch horizontal drain pipe?
A) 1/8 inch per foot
B) 1/4 inch per foot
C) 1/8 to 1/4 inch per foot
D) 1/2 inch per foot
The slope ensures proper drainage by gravity without causing blockages.
7. Which type of valve is used to stop water flow completely?
A) Check valve
B) Gate valve
C) Ball valve
D) Pressure-reducing valve
Ball valves provide a full shutoff and are reliable for controlling water flow.
8. What is the minimum vent size for a single fixture?
A) 1 inch
B) 1.25 inches
C) 1.5 inches
D) 2 inches
The vent allows sewer gases to escape and ensures proper drainage; 1.5 inches
is the minimum standard for a single fixture.
9. What is the maximum distance a water closet can be from its vent?
A) 2 feet
B) 4 feet
C) 6 feet
, D) 8 feet
Venting distance limits prevent siphoning of traps and ensure proper airflow.
10. What is the purpose of a backflow preventer?
A) Increase water pressure
B) Prevent contaminated water from flowing back into the potable supply
C) Filter sediment
D) Reduce water temperature
Backflow preventers protect the public water supply from contamination.
11. What is the minimum distance a water heater must be installed from a
gas-fired appliance?
A) 6 inches
B) 12 inches
C) 18 inches
D) 24 inches
Maintaining clearance prevents heat damage and ensures safe operation.
12. What is the maximum temperature allowed for domestic hot water at the
fixture?
A) 110°F
B) 120°F
C) 125°F
D) 140°F
This prevents scalding while providing sufficient hot water for use.
13. Which of the following is a common material for sanitary sewer piping?
A) Copper
B) PVC
C) Aluminum
D) PEX
PVC is durable, lightweight, and corrosion-resistant, making it ideal for sanitary
sewer systems.
14. How many plumbing fixtures are allowed on a 1.5-inch branch drain?
A) 1
B) 2
C) 3
