Wisconsin Journeyman Plumber Exam
Practice Questions And Correct Answers
(Verified Answers) Plus Rationales 2026
Q&A | Instant Download Pdf
1. Which pipe material is commonly approved for potable water
distribution systems in modern plumbing installations?
A. Galvanized steel
B. Copper tubing
C. Cast iron
D. Vitrified clay
Copper tubing is widely used for potable water due to its corrosion
resistance, durability, and compliance with plumbing codes for
drinking water systems.
2. What is the primary purpose of a plumbing vent system?
A. Increase water pressure
B. Prevent pipe freezing
C. Allow sewer gases to escape and maintain trap seal integrity
D. Increase drainage speed
, Vent systems equalize air pressure in drainage pipes, preventing
siphoning of traps and allowing sewer gases to safely exit through
the vent stack.
3. The minimum slope for a 3-inch horizontal drain pipe is typically:
A. 1/16 inch per foot
B. 1/8 inch per foot
C. 1/4 inch per foot
D. 1/2 inch per foot
Plumbing codes generally require a minimum slope of 1/8 inch per
foot for 3-inch drains to ensure proper gravity flow and prevent
solids buildup.
4. Which fitting is used to change the direction of a drain line by 90
degrees with minimal flow restriction?
A. Tee
B. Wye
C. Long sweep elbow
D. Cross
A long sweep elbow reduces turbulence and clogging risk compared
to sharp 90-degree fittings in drainage systems.
5. What is the function of a P-trap?
A. Increase water pressure
B. Prevent sewer gas from entering the building
C. Regulate water temperature
, D. Filter debris from wastewater
A P-trap holds a water seal that blocks sewer gases while allowing
wastewater to pass through freely.
6. Which tool is used to cut large diameter plastic pipe accurately?
A. Pipe wrench
B. Hacksaw
C. Ratchet pipe cutter
D. Chisel
A ratchet pipe cutter provides clean, square cuts on large plastic
pipes, improving joint integrity.
7. What is the standard test pressure for a typical water supply system
inspection?
A. 25 psi
B. 30 psi
C. 100 psi
D. 150 psi
Water supply systems are commonly tested at 100 psi to ensure leak-
free performance under pressure.
8. Which of the following is a common cause of water hammer?
A. Excess pipe insulation
B. Sudden valve closure
C. Oversized pipes
D. Low water pressure
, Water hammer occurs when flowing water is abruptly stopped,
creating shock waves in the piping system.
9. What is the purpose of a backflow preventer?
A. Increase flow rate
B. Reduce pipe noise
C. Prevent contamination of potable water supply
D. Increase water pressure
Backflow preventers ensure contaminated water does not reverse
flow into clean water systems.
10. Which material is most commonly used for DWV (Drain, Waste,
Vent) systems in residential construction today?
A. Copper
B. Steel
C. PVC plastic
D. Lead
PVC is widely used in DWV systems because it is lightweight,
corrosion-resistant, and cost-effective.
11. What does “DWV” stand for in plumbing?
A. Drain Water Valve
B. Domestic Water Volume
C. Drain, Waste, and Vent
D. Direct Water Ventilation
Practice Questions And Correct Answers
(Verified Answers) Plus Rationales 2026
Q&A | Instant Download Pdf
1. Which pipe material is commonly approved for potable water
distribution systems in modern plumbing installations?
A. Galvanized steel
B. Copper tubing
C. Cast iron
D. Vitrified clay
Copper tubing is widely used for potable water due to its corrosion
resistance, durability, and compliance with plumbing codes for
drinking water systems.
2. What is the primary purpose of a plumbing vent system?
A. Increase water pressure
B. Prevent pipe freezing
C. Allow sewer gases to escape and maintain trap seal integrity
D. Increase drainage speed
, Vent systems equalize air pressure in drainage pipes, preventing
siphoning of traps and allowing sewer gases to safely exit through
the vent stack.
3. The minimum slope for a 3-inch horizontal drain pipe is typically:
A. 1/16 inch per foot
B. 1/8 inch per foot
C. 1/4 inch per foot
D. 1/2 inch per foot
Plumbing codes generally require a minimum slope of 1/8 inch per
foot for 3-inch drains to ensure proper gravity flow and prevent
solids buildup.
4. Which fitting is used to change the direction of a drain line by 90
degrees with minimal flow restriction?
A. Tee
B. Wye
C. Long sweep elbow
D. Cross
A long sweep elbow reduces turbulence and clogging risk compared
to sharp 90-degree fittings in drainage systems.
5. What is the function of a P-trap?
A. Increase water pressure
B. Prevent sewer gas from entering the building
C. Regulate water temperature
, D. Filter debris from wastewater
A P-trap holds a water seal that blocks sewer gases while allowing
wastewater to pass through freely.
6. Which tool is used to cut large diameter plastic pipe accurately?
A. Pipe wrench
B. Hacksaw
C. Ratchet pipe cutter
D. Chisel
A ratchet pipe cutter provides clean, square cuts on large plastic
pipes, improving joint integrity.
7. What is the standard test pressure for a typical water supply system
inspection?
A. 25 psi
B. 30 psi
C. 100 psi
D. 150 psi
Water supply systems are commonly tested at 100 psi to ensure leak-
free performance under pressure.
8. Which of the following is a common cause of water hammer?
A. Excess pipe insulation
B. Sudden valve closure
C. Oversized pipes
D. Low water pressure
, Water hammer occurs when flowing water is abruptly stopped,
creating shock waves in the piping system.
9. What is the purpose of a backflow preventer?
A. Increase flow rate
B. Reduce pipe noise
C. Prevent contamination of potable water supply
D. Increase water pressure
Backflow preventers ensure contaminated water does not reverse
flow into clean water systems.
10. Which material is most commonly used for DWV (Drain, Waste,
Vent) systems in residential construction today?
A. Copper
B. Steel
C. PVC plastic
D. Lead
PVC is widely used in DWV systems because it is lightweight,
corrosion-resistant, and cost-effective.
11. What does “DWV” stand for in plumbing?
A. Drain Water Valve
B. Domestic Water Volume
C. Drain, Waste, and Vent
D. Direct Water Ventilation
