Journeyman Plumber Licensing Exam d d d
Practice Questions And Correct Answers ( d d d d d
Verified Answers) Plus Rationales 2026 Q d d d d d
&A | Instant Download Pdf
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1. What is the minimum size of a trap arm for a water closet?
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A) 2 inches
d
B) 3 inches
d
C) 4 inches
d
D) 1½ inches
d
Rationale: Water closets require a minimum 3-
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inch trap arm to properly handle waste discharge and prevent clogging.
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2. The main purpose of a plumbing vent is to:
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A) Provide water to fixtures d d d
B) Equalize air pressure in the drainage system
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C) Stop sewer gas leaks
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D) Increase water flow d d
,Rationale: Vents prevent negative pressure that could siphon traps and allo
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w smooth waste flow.
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3. What type of fitting is used to connect two pipes of different sizes in a s
d d d d d d d d d d d d d d d
traight line? d
A) Elbow
B) Reducer coupling d
C) Cross
D) Wye
Rationale: A reducer coupling transitions between different pipe diameters
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while maintaining alignment.
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4. The minimum slope for a 3-inch horizontal drainage pipe is:
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A) ¼ inch per foot
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B) ⅛ inch per foot
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C) ½ inch per foot
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D) 1 inch per foot
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Rationale: ⅛ inch per foot is sufficient for 3-
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inch or larger pipes to maintain flow without excessive velocity.
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5. A plumbing trap must:
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A) Be vented on the outlet side only
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,B) Hold at least 4 inches of water
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C) Seal against sewer gases
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D) Be installed vertically
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Rationale: The trap’s water seal blocks sewer gases from entering living spa
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ces.
6. What type of valve is commonly used on gas lines?
d d d d d d d d d
A) Gate valve d
B) Globe valve d
C) Ball valve d
D) Check valve d
Rationale: Ball valves allow quick shutoff and are suitable for gas line safety.
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7. A water heater’s temperature relief valve must discharge:
d d d d d d d
A) Into a vent stack
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B) Into a floor drain
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C) Onto the floor d d
D) To an approved discharge location by gravity
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Rationale: T&P valves must safely discharge by gravity to prevent scalding o
d d d d d d d d d d d
r pressure buildup.
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, 8. Which of the following materials is approved for underground drainage
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piping?
A) Galvanized steel d
B) PVC (Schedule 40) d d
C) Copper DWV d
D) Lead
Rationale: PVC Schedule 40 is corrosion-
d d d d d
resistant and widely approved for underground use.
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9. The maximum trap seal depth allowed by code is typically:
d d d d d d d d d
A) ½ inchd
B) 1 inch
d
C) 4 inches
d
D) 6 inches
d
Rationale: Excessive trap seal depth can slow drainage and lead to siphonag
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e.
10. What is the minimum distance between a cleanout and the wall it faces?
d d d d d d d d d d d d
A) 6 inches
d
B) 12 inches d
C) 18 inches d
D) 24 inches d
Practice Questions And Correct Answers ( d d d d d
Verified Answers) Plus Rationales 2026 Q d d d d d
&A | Instant Download Pdf
d d d d
1. What is the minimum size of a trap arm for a water closet?
d d d d d d d d d d d d d
A) 2 inches
d
B) 3 inches
d
C) 4 inches
d
D) 1½ inches
d
Rationale: Water closets require a minimum 3-
d d d d d d
inch trap arm to properly handle waste discharge and prevent clogging.
d d d d d d d d d d
2. The main purpose of a plumbing vent is to:
d d d d d d d d
A) Provide water to fixtures d d d
B) Equalize air pressure in the drainage system
d d d d d d
C) Stop sewer gas leaks
d d d
D) Increase water flow d d
,Rationale: Vents prevent negative pressure that could siphon traps and allo
d d d d d d d d d d
w smooth waste flow.
d d d
3. What type of fitting is used to connect two pipes of different sizes in a s
d d d d d d d d d d d d d d d
traight line? d
A) Elbow
B) Reducer coupling d
C) Cross
D) Wye
Rationale: A reducer coupling transitions between different pipe diameters
d d d d d d d d d
while maintaining alignment.
d d
4. The minimum slope for a 3-inch horizontal drainage pipe is:
d d d d d d d d d
A) ¼ inch per foot
d d d
B) ⅛ inch per foot
d d d
C) ½ inch per foot
d d d
D) 1 inch per foot
d d d
Rationale: ⅛ inch per foot is sufficient for 3-
d d d d d d d d
inch or larger pipes to maintain flow without excessive velocity.
d d d d d d d d d
5. A plumbing trap must:
d d d
A) Be vented on the outlet side only
d d d d d d
,B) Hold at least 4 inches of water
d d d d d d
C) Seal against sewer gases
d d d
D) Be installed vertically
d d
Rationale: The trap’s water seal blocks sewer gases from entering living spa
d d d d d d d d d d d
ces.
6. What type of valve is commonly used on gas lines?
d d d d d d d d d
A) Gate valve d
B) Globe valve d
C) Ball valve d
D) Check valve d
Rationale: Ball valves allow quick shutoff and are suitable for gas line safety.
d d d d d d d d d d d d
7. A water heater’s temperature relief valve must discharge:
d d d d d d d
A) Into a vent stack
d d d
B) Into a floor drain
d d d
C) Onto the floor d d
D) To an approved discharge location by gravity
d d d d d d
Rationale: T&P valves must safely discharge by gravity to prevent scalding o
d d d d d d d d d d d
r pressure buildup.
d d
, 8. Which of the following materials is approved for underground drainage
d d d d d d d d d d
piping?
A) Galvanized steel d
B) PVC (Schedule 40) d d
C) Copper DWV d
D) Lead
Rationale: PVC Schedule 40 is corrosion-
d d d d d
resistant and widely approved for underground use.
d d d d d d
9. The maximum trap seal depth allowed by code is typically:
d d d d d d d d d
A) ½ inchd
B) 1 inch
d
C) 4 inches
d
D) 6 inches
d
Rationale: Excessive trap seal depth can slow drainage and lead to siphonag
d d d d d d d d d d d
e.
10. What is the minimum distance between a cleanout and the wall it faces?
d d d d d d d d d d d d
A) 6 inches
d
B) 12 inches d
C) 18 inches d
D) 24 inches d
