Texas Journeyman Plumber Exam Verified Questions,
Correct Answers, and Detailed Explanations for
Science Students||Already Graded A+
1. What is the minimum slope for a 3-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
Pipes 3 inches and larger require a minimum slope of 1/8 inch per
foot for proper drainage.
2. What is the minimum trap seal depth?
A. 1 inch
B. 2 inches
C. 3 inches
D. 4 inches
Trap seals must be between 2–4 inches to prevent sewer gases from
entering the building.
3. What type of pipe is approved for underground water service?
A. PVC DWV
B. ABS foam core
C. Type K copper
D. EMT conduit
Type K copper has the thickest wall and is approved for underground
water service.
,4. What is the maximum distance a water closet can be from its
vent (3-inch trap arm)?
A. 4 feet
B. 6 feet
C. 6–8 feet (depending on code)
D. 12 feet
Trap arm distances are limited to prevent siphoning; 3-inch lines
typically allow up to about 6 feet (IPC up to 8).
5. What is the minimum size vent for a water closet?
A. 1 1/4 inch
B. 1 1/2 inch
C. 2 inch
D. 3 inch
Water closets require a minimum 2-inch vent.
6. A cleanout is required at what interval on horizontal drainage
lines?
A. Every 50 feet
B. Every 75 feet
C. Every 100 feet
D. Every 150 feet
Cleanouts are required every 100 feet and at direction changes.
7. What fitting should be used for a horizontal to horizontal
drainage change?
, A. Sanitary tee
B. Wye or combo
C. Vent tee
D. Coupling
Sanitary tees are not permitted for horizontal drainage flow changes.
8. What is the minimum temperature setting for a residential water
heater?
A. 100°F
B. 120°F
C. 140°F
D. 160°F
120°F helps prevent scalding and reduces energy use.
9. What device protects potable water from contamination?
A. Pressure regulator
B. Expansion tank
C. Backflow preventer
D. Check valve
Backflow prevention devices protect the water supply.
10. What is the minimum size water service pipe for a single-family
home?
A. 1/2 inch
B. 3/4 inch
C. 1 inch
D. 1 1/2 inch
Most codes require at least 3/4-inch service for residential supply.
Correct Answers, and Detailed Explanations for
Science Students||Already Graded A+
1. What is the minimum slope for a 3-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
Pipes 3 inches and larger require a minimum slope of 1/8 inch per
foot for proper drainage.
2. What is the minimum trap seal depth?
A. 1 inch
B. 2 inches
C. 3 inches
D. 4 inches
Trap seals must be between 2–4 inches to prevent sewer gases from
entering the building.
3. What type of pipe is approved for underground water service?
A. PVC DWV
B. ABS foam core
C. Type K copper
D. EMT conduit
Type K copper has the thickest wall and is approved for underground
water service.
,4. What is the maximum distance a water closet can be from its
vent (3-inch trap arm)?
A. 4 feet
B. 6 feet
C. 6–8 feet (depending on code)
D. 12 feet
Trap arm distances are limited to prevent siphoning; 3-inch lines
typically allow up to about 6 feet (IPC up to 8).
5. What is the minimum size vent for a water closet?
A. 1 1/4 inch
B. 1 1/2 inch
C. 2 inch
D. 3 inch
Water closets require a minimum 2-inch vent.
6. A cleanout is required at what interval on horizontal drainage
lines?
A. Every 50 feet
B. Every 75 feet
C. Every 100 feet
D. Every 150 feet
Cleanouts are required every 100 feet and at direction changes.
7. What fitting should be used for a horizontal to horizontal
drainage change?
, A. Sanitary tee
B. Wye or combo
C. Vent tee
D. Coupling
Sanitary tees are not permitted for horizontal drainage flow changes.
8. What is the minimum temperature setting for a residential water
heater?
A. 100°F
B. 120°F
C. 140°F
D. 160°F
120°F helps prevent scalding and reduces energy use.
9. What device protects potable water from contamination?
A. Pressure regulator
B. Expansion tank
C. Backflow preventer
D. Check valve
Backflow prevention devices protect the water supply.
10. What is the minimum size water service pipe for a single-family
home?
A. 1/2 inch
B. 3/4 inch
C. 1 inch
D. 1 1/2 inch
Most codes require at least 3/4-inch service for residential supply.
