JOURNEYMAN PLUMBER LICENSE EXAM
QUESTIONS AND CORRECT ANSWERS
(VERIFIED ANSWERS) PLUS RATIONALES
2026 Q&A | INSTANT DOWNLOAD PDF
1. What is the minimum slope for a 3-inch horizontal drainage pipe?
• 1/8 inch per foot
• 1/4 inch per foot
• 1/2 inch per foot
• No slope required
A 1/4 inch per foot slope ensures proper gravity flow and minimizes
solids buildup.
2. What type of fitting is used to connect two pipes of different sizes in a
straight line?
• Tee
• Reducer coupling
• Elbow
,• Union
Reducer couplings allow for a smooth transition between different
pipe sizes.
3. What is the purpose of a trap in a plumbing system?
• To regulate pressure
• To prevent sewer gases from entering the building
• To filter debris
• To increase water pressure
Traps retain water to form a barrier against sewer gas entry.
4. Which material is most commonly used for residential water supply
lines?
• PEX
• Cast iron
• PVC
• ABS
PEX is flexible, resistant to scale and chlorine, and easier to install.
5. A branch vent connects to:
• A waste pipe and a vent stack
• Only to a fixture
• The building sewer
• The hot water line
Branch vents provide air to waste lines and connect to the main vent
system.
, 6. What is the function of a backflow preventer?
• Increase flow rate
• Reduce noise
• Prevent contamination of potable water
• Reduce water pressure
It protects potable water from reverse flow contamination.
7. Which code sets minimum standards for plumbing systems?
• National Fire Protection Association
• Uniform Plumbing Code (UPC)
• National Electrical Code
• International Mechanical Code
The UPC governs plumbing design and installation.
8. A water heater relief valve protects against:
• Low temperatures
• Excessive pressure and temperature
• Sediment buildup
• Water hammer
Relief valves prevent tank rupture due to overheating or
overpressure.
9. What type of valve is used for throttling flow?
• Gate valve
• Check valve
QUESTIONS AND CORRECT ANSWERS
(VERIFIED ANSWERS) PLUS RATIONALES
2026 Q&A | INSTANT DOWNLOAD PDF
1. What is the minimum slope for a 3-inch horizontal drainage pipe?
• 1/8 inch per foot
• 1/4 inch per foot
• 1/2 inch per foot
• No slope required
A 1/4 inch per foot slope ensures proper gravity flow and minimizes
solids buildup.
2. What type of fitting is used to connect two pipes of different sizes in a
straight line?
• Tee
• Reducer coupling
• Elbow
,• Union
Reducer couplings allow for a smooth transition between different
pipe sizes.
3. What is the purpose of a trap in a plumbing system?
• To regulate pressure
• To prevent sewer gases from entering the building
• To filter debris
• To increase water pressure
Traps retain water to form a barrier against sewer gas entry.
4. Which material is most commonly used for residential water supply
lines?
• PEX
• Cast iron
• PVC
• ABS
PEX is flexible, resistant to scale and chlorine, and easier to install.
5. A branch vent connects to:
• A waste pipe and a vent stack
• Only to a fixture
• The building sewer
• The hot water line
Branch vents provide air to waste lines and connect to the main vent
system.
, 6. What is the function of a backflow preventer?
• Increase flow rate
• Reduce noise
• Prevent contamination of potable water
• Reduce water pressure
It protects potable water from reverse flow contamination.
7. Which code sets minimum standards for plumbing systems?
• National Fire Protection Association
• Uniform Plumbing Code (UPC)
• National Electrical Code
• International Mechanical Code
The UPC governs plumbing design and installation.
8. A water heater relief valve protects against:
• Low temperatures
• Excessive pressure and temperature
• Sediment buildup
• Water hammer
Relief valves prevent tank rupture due to overheating or
overpressure.
9. What type of valve is used for throttling flow?
• Gate valve
• Check valve
