Texas Journeyman Plumber License
Exam Questions And Correct Answers
(Verified Answers) Plus Rationales 2026
Q&A | Instant Download Pdf
1. What is the minimum depth for burying water service piping in Texas?
a) 6 inches
b) 12 inches
c) 12 inches below the frost line
d) 24 inches
Rationale: The Texas Plumbing Code requires water lines to be buried at
least 12 inches below the frost line to prevent freezing.
2. Which of the following materials is not approved for water distribution
piping inside a building?
a) Copper
b) CPVC
c) ABS
d) PEX
Rationale: ABS is not approved for water distribution piping; it is typically
used for drainage, waste, and vent piping.
,3. What is the purpose of a trap primer?
a) Increases water pressure
b) Prevents freezing in pipes
c) Maintains a water seal in a trap
d) Filters sediment from water
Rationale: A trap primer maintains the water seal in a trap, preventing
sewer gases from entering the building.
4. The developed length of a pipe run refers to:
a) Straight-line distance
b) The shortest path between fixtures
c) Total length including all fittings
d) Vertical distance only
Rationale: Developed length accounts for the actual pipe run, including all
offsets and fittings.
5. What size water service is required for a single-family residence with 3
bathrooms?
a) ¾ inch
b) 1 inch
c) ½ inch
d) 1¼ inch
Rationale: A 1-inch water service is typically required to meet the demand
of multiple fixtures in a 3-bathroom house.
,6. What is the maximum horizontal spacing between supports for 1½-inch
PVC DWV piping?
a) 4 feet
b) 6 feet
c) 4 feet and at every joint
d) 8 feet
Rationale: PVC piping must be supported at 4-foot intervals and at every
joint to maintain proper slope and prevent sagging.
7. A 3-inch drain pipe must have a minimum slope of:
a) ⅛ inch per foot
b) ¼ inch per foot
c) ½ inch per foot
d) Level is acceptable
Rationale: According to code, a 3-inch pipe requires a minimum slope of ¼
inch per foot to ensure proper drainage.
8. A plumbing vent must terminate at least how far above the roof
surface?
a) 3 inches
b) 6 inches
c) 6 inches or as required by local code
d) 12 inches
Rationale: Most codes require a minimum of 6 inches above the roof to
prevent blockage and backflow of gases.
, 9. Which fitting is used to change direction in a vertical DWV system?
a) Sanitary tee
b) Wye
c) Elbow
d) Coupling
Rationale: A wye fitting allows a smooth transition in direction in vertical
drainage systems to avoid clogs.
10. What type of valve is required at the base of every water riser?
a) Ball valve
b) Full open valve
c) Check valve
d) Gate valve
Rationale: A full open valve is used to control flow without creating
obstruction in the line.
11. When testing drainage and vent systems with water, the minimum
head of water shall be:
a) 5 feet
b) 10 feet
c) 15 feet
d) 20 feet
Rationale: A 10-foot head of water is required to test the drainage and
vent systems for leaks.
Exam Questions And Correct Answers
(Verified Answers) Plus Rationales 2026
Q&A | Instant Download Pdf
1. What is the minimum depth for burying water service piping in Texas?
a) 6 inches
b) 12 inches
c) 12 inches below the frost line
d) 24 inches
Rationale: The Texas Plumbing Code requires water lines to be buried at
least 12 inches below the frost line to prevent freezing.
2. Which of the following materials is not approved for water distribution
piping inside a building?
a) Copper
b) CPVC
c) ABS
d) PEX
Rationale: ABS is not approved for water distribution piping; it is typically
used for drainage, waste, and vent piping.
,3. What is the purpose of a trap primer?
a) Increases water pressure
b) Prevents freezing in pipes
c) Maintains a water seal in a trap
d) Filters sediment from water
Rationale: A trap primer maintains the water seal in a trap, preventing
sewer gases from entering the building.
4. The developed length of a pipe run refers to:
a) Straight-line distance
b) The shortest path between fixtures
c) Total length including all fittings
d) Vertical distance only
Rationale: Developed length accounts for the actual pipe run, including all
offsets and fittings.
5. What size water service is required for a single-family residence with 3
bathrooms?
a) ¾ inch
b) 1 inch
c) ½ inch
d) 1¼ inch
Rationale: A 1-inch water service is typically required to meet the demand
of multiple fixtures in a 3-bathroom house.
,6. What is the maximum horizontal spacing between supports for 1½-inch
PVC DWV piping?
a) 4 feet
b) 6 feet
c) 4 feet and at every joint
d) 8 feet
Rationale: PVC piping must be supported at 4-foot intervals and at every
joint to maintain proper slope and prevent sagging.
7. A 3-inch drain pipe must have a minimum slope of:
a) ⅛ inch per foot
b) ¼ inch per foot
c) ½ inch per foot
d) Level is acceptable
Rationale: According to code, a 3-inch pipe requires a minimum slope of ¼
inch per foot to ensure proper drainage.
8. A plumbing vent must terminate at least how far above the roof
surface?
a) 3 inches
b) 6 inches
c) 6 inches or as required by local code
d) 12 inches
Rationale: Most codes require a minimum of 6 inches above the roof to
prevent blockage and backflow of gases.
, 9. Which fitting is used to change direction in a vertical DWV system?
a) Sanitary tee
b) Wye
c) Elbow
d) Coupling
Rationale: A wye fitting allows a smooth transition in direction in vertical
drainage systems to avoid clogs.
10. What type of valve is required at the base of every water riser?
a) Ball valve
b) Full open valve
c) Check valve
d) Gate valve
Rationale: A full open valve is used to control flow without creating
obstruction in the line.
11. When testing drainage and vent systems with water, the minimum
head of water shall be:
a) 5 feet
b) 10 feet
c) 15 feet
d) 20 feet
Rationale: A 10-foot head of water is required to test the drainage and
vent systems for leaks.
