CT Limited Plumbing Journeyperson (P-4)
Exam 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 water from freezing
C. To prevent sewer gases from entering a building
D. To improve drainage velocity
Rationale: A plumbing trap retains a water seal that blocks sewer
gases from traveling through the drainage system and entering
occupied spaces. The trap must be properly sized, installed, and
protected from siphonage or backpressure.
2. Which fitting is commonly used to change the direction of a
drainage pipe by 90 degrees while maintaining proper drainage
flow?
,A. Sanitary tee
B. Long-sweep quarter bend
C. Reducing coupling
D. Straight coupling
Rationale: A long-sweep quarter bend provides a gradual change in
direction, reducing turbulence and the likelihood of blockage.
Drainage fittings are designed with smoother transitions than many
fittings used in pressurized water piping.
3. What is the main function of a cleanout in a drainage system?
A. To regulate water temperature
B. To increase pipe pressure
C. To prevent trap evaporation
D. To provide access for cleaning and clearing the drainage piping
Rationale: Cleanouts provide accessible openings into drainage piping
so that blockages can be removed and the piping can be serviced.
They must be installed where required and kept accessible.
4. Which material is commonly used for potable water distribution
piping?
A. Cast iron soil pipe
B. Copper tubing
,C. Vitrified clay pipe
D. Concrete pipe
Rationale: Copper tubing is widely used for potable water distribution
because it is durable, corrosion resistant under appropriate
conditions, and suitable for hot and cold water service.
5. What is the purpose of a water shutoff valve?
A. To increase water temperature
B. To remove sewer gases
C. To control or stop water flow through a piping section
D. To increase drainage slope
Rationale: A shutoff valve allows a fixture, appliance, or section of
piping to be isolated for maintenance or repair without necessarily
shutting down the entire building water system.
6. Which fitting is generally appropriate for connecting a branch
drain to a horizontal drainage pipe?
A. Standard water-service tee
B. Wye fitting
C. Cross fitting
D. Straight coupling
, Rationale: A wye provides a gradual branch connection that promotes
smoother drainage flow. Drainage fittings must be selected and
installed to maintain proper flow and minimize turbulence.
7. What does the term “DWV” stand for?
A. Domestic Water Valve
B. Drain Water Vent
C. Drain, Waste, and Vent
D. Domestic Waste Vessel
Rationale: DWV refers to the drainage, waste, and vent portion of a
plumbing system. These systems remove wastewater and provide
ventilation necessary for proper drainage and protection of trap seals.
8. Why must a plumbing vent system be properly designed?
A. To increase water heater temperature
B. To eliminate the need for traps
C. To protect trap seals and allow drainage systems to operate
properly
D. To increase water pressure at fixtures
Rationale: Venting balances pressures within the drainage system and
helps prevent trap seal loss caused by siphonage or pressure
fluctuations. Proper venting also supports efficient drainage.
Exam 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 water from freezing
C. To prevent sewer gases from entering a building
D. To improve drainage velocity
Rationale: A plumbing trap retains a water seal that blocks sewer
gases from traveling through the drainage system and entering
occupied spaces. The trap must be properly sized, installed, and
protected from siphonage or backpressure.
2. Which fitting is commonly used to change the direction of a
drainage pipe by 90 degrees while maintaining proper drainage
flow?
,A. Sanitary tee
B. Long-sweep quarter bend
C. Reducing coupling
D. Straight coupling
Rationale: A long-sweep quarter bend provides a gradual change in
direction, reducing turbulence and the likelihood of blockage.
Drainage fittings are designed with smoother transitions than many
fittings used in pressurized water piping.
3. What is the main function of a cleanout in a drainage system?
A. To regulate water temperature
B. To increase pipe pressure
C. To prevent trap evaporation
D. To provide access for cleaning and clearing the drainage piping
Rationale: Cleanouts provide accessible openings into drainage piping
so that blockages can be removed and the piping can be serviced.
They must be installed where required and kept accessible.
4. Which material is commonly used for potable water distribution
piping?
A. Cast iron soil pipe
B. Copper tubing
,C. Vitrified clay pipe
D. Concrete pipe
Rationale: Copper tubing is widely used for potable water distribution
because it is durable, corrosion resistant under appropriate
conditions, and suitable for hot and cold water service.
5. What is the purpose of a water shutoff valve?
A. To increase water temperature
B. To remove sewer gases
C. To control or stop water flow through a piping section
D. To increase drainage slope
Rationale: A shutoff valve allows a fixture, appliance, or section of
piping to be isolated for maintenance or repair without necessarily
shutting down the entire building water system.
6. Which fitting is generally appropriate for connecting a branch
drain to a horizontal drainage pipe?
A. Standard water-service tee
B. Wye fitting
C. Cross fitting
D. Straight coupling
, Rationale: A wye provides a gradual branch connection that promotes
smoother drainage flow. Drainage fittings must be selected and
installed to maintain proper flow and minimize turbulence.
7. What does the term “DWV” stand for?
A. Domestic Water Valve
B. Drain Water Vent
C. Drain, Waste, and Vent
D. Domestic Waste Vessel
Rationale: DWV refers to the drainage, waste, and vent portion of a
plumbing system. These systems remove wastewater and provide
ventilation necessary for proper drainage and protection of trap seals.
8. Why must a plumbing vent system be properly designed?
A. To increase water heater temperature
B. To eliminate the need for traps
C. To protect trap seals and allow drainage systems to operate
properly
D. To increase water pressure at fixtures
Rationale: Venting balances pressures within the drainage system and
helps prevent trap seal loss caused by siphonage or pressure
fluctuations. Proper venting also supports efficient drainage.
