Minnesota Journeyman Plumber Examination
Questions and Correct Answers (Verified
Answers) Plus Rationale 2027 Q&A| Instant
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1. What is the primary purpose of a plumbing trap?
A. To increase water pressure
B. To prevent freezing in the drainage system
C. To prevent sewer gases from entering a building
D. To increase drainage velocity
Answer: C. To prevent sewer gases from entering a building
Rationale: A plumbing trap retains a water seal that separates the
interior of a building from the drainage system. This water seal helps
prevent sewer gases and odors from entering occupied spaces while
still allowing wastewater to flow through the fixture drain.
2. Which plumbing system carries water from the building's water
supply to fixtures?
,A. Sanitary drainage system
B. Vent system
C. Water distribution system
D. Storm drainage system
Answer: C. Water distribution system
Rationale: The water distribution system consists of piping, valves,
fittings, and related components that convey potable or otherwise
permitted water from the service or supply source to plumbing
fixtures and other points of use.
3. What is the primary function of a plumbing vent?
A. To supply hot water
B. To maintain proper air pressure in the drainage system
C. To increase water pressure
D. To collect wastewater
Answer: B. To maintain proper air pressure in the drainage system
Rationale: Drainage-system vents allow air to enter and leave the
piping system. Proper venting helps protect trap seals from pressure
fluctuations that could otherwise cause siphonage or backpressure.
4. Which fitting is commonly used to change the direction of a
drainage pipe by approximately 90 degrees?
,A. Sanitary tee
B. Long-sweep elbow
C. Coupling
D. Reducer
Answer: B. Long-sweep elbow
Rationale: A long-sweep fitting provides a gradual change in
direction, reducing resistance to drainage flow and helping prevent
blockages. Drainage fittings are designed differently from many
fittings used in pressurized water piping.
5. What does the term "potable water" mean?
A. Water used only for irrigation
B. Water suitable for drinking
C. Water containing disinfectants only
D. Reclaimed wastewater
Answer: B. Water suitable for drinking
Rationale: Potable water is water considered safe and suitable for
human consumption. Plumbing systems supplying potable water must
be protected from contamination and cross-connections.
6. What is a cross-connection?
, A. A connection between two drain lines
B. A connection between a vent and a drain
C. A connection through which potable water could become
contaminated
D. A connection between two identical water lines
Answer: C. A connection through which potable water could become
contaminated
Rationale: A cross-connection creates a potential pathway for
contaminants to enter the potable water supply. Backflow prevention
methods are used to protect potable water from these hazards.
7. What is backflow?
A. Water flowing in the intended direction
B. Unwanted reversal of water flow
C. Water flowing through a vent
D. Wastewater flowing into a trap
Answer: B. Unwanted reversal of water flow
Rationale: Backflow occurs when water or another substance moves
in the opposite direction from normal flow. Backflow can be caused by
backpressure or backsiphonage and may introduce contaminants into
potable water.
Questions and Correct Answers (Verified
Answers) Plus Rationale 2027 Q&A| Instant
Download Pdf
1. What is the primary purpose of a plumbing trap?
A. To increase water pressure
B. To prevent freezing in the drainage system
C. To prevent sewer gases from entering a building
D. To increase drainage velocity
Answer: C. To prevent sewer gases from entering a building
Rationale: A plumbing trap retains a water seal that separates the
interior of a building from the drainage system. This water seal helps
prevent sewer gases and odors from entering occupied spaces while
still allowing wastewater to flow through the fixture drain.
2. Which plumbing system carries water from the building's water
supply to fixtures?
,A. Sanitary drainage system
B. Vent system
C. Water distribution system
D. Storm drainage system
Answer: C. Water distribution system
Rationale: The water distribution system consists of piping, valves,
fittings, and related components that convey potable or otherwise
permitted water from the service or supply source to plumbing
fixtures and other points of use.
3. What is the primary function of a plumbing vent?
A. To supply hot water
B. To maintain proper air pressure in the drainage system
C. To increase water pressure
D. To collect wastewater
Answer: B. To maintain proper air pressure in the drainage system
Rationale: Drainage-system vents allow air to enter and leave the
piping system. Proper venting helps protect trap seals from pressure
fluctuations that could otherwise cause siphonage or backpressure.
4. Which fitting is commonly used to change the direction of a
drainage pipe by approximately 90 degrees?
,A. Sanitary tee
B. Long-sweep elbow
C. Coupling
D. Reducer
Answer: B. Long-sweep elbow
Rationale: A long-sweep fitting provides a gradual change in
direction, reducing resistance to drainage flow and helping prevent
blockages. Drainage fittings are designed differently from many
fittings used in pressurized water piping.
5. What does the term "potable water" mean?
A. Water used only for irrigation
B. Water suitable for drinking
C. Water containing disinfectants only
D. Reclaimed wastewater
Answer: B. Water suitable for drinking
Rationale: Potable water is water considered safe and suitable for
human consumption. Plumbing systems supplying potable water must
be protected from contamination and cross-connections.
6. What is a cross-connection?
, A. A connection between two drain lines
B. A connection between a vent and a drain
C. A connection through which potable water could become
contaminated
D. A connection between two identical water lines
Answer: C. A connection through which potable water could become
contaminated
Rationale: A cross-connection creates a potential pathway for
contaminants to enter the potable water supply. Backflow prevention
methods are used to protect potable water from these hazards.
7. What is backflow?
A. Water flowing in the intended direction
B. Unwanted reversal of water flow
C. Water flowing through a vent
D. Wastewater flowing into a trap
Answer: B. Unwanted reversal of water flow
Rationale: Backflow occurs when water or another substance moves
in the opposite direction from normal flow. Backflow can be caused by
backpressure or backsiphonage and may introduce contaminants into
potable water.
