Arizona AZ C-37 (CR-37) Plumbing Contractor License Practice Exam – Complete State Rules, Trade Questions, and Detailed Explanations (Pass on First Try)

AZ C-37 (CR-37) Plumbing Contractor
Practice Exam – Questions & Answers 2026



Question 1
In plumbing terminology, what does the term "fixture unit" refer to?

A. The volume of water supplied to a fixture
B. The load a plumbing fixture imposes on the drainage system
C. The number of fixtures connected to a water main
D. The pressure rating of a fixture

*Correct Answer: B. *

Rationale: Fixture units quantify the probable discharge from fixtures and
help in designing drainage and vent systems to ensure proper flow and
sizing. The concept was developed to standardize the load that different
fixtures place on a system.




Question 2
Which property of water causes it to exert pressure in a closed plumbing
system?

A. Viscosity
B. Surface tension
C. Hydrostatic pressure due to gravity
D. Capillarity

*Correct Answer: C. *

,Rationale: Hydrostatic pressure arises from the weight of water in a column,
exerting force in a closed system, especially in vertical piping. This is the
fundamental principle behind water pressure in plumbing systems.




Question 3
According to most plumbing codes, the maximum distance a trap may be
located from its vent is determined by:

A. Water heater capacity
B. Pipe slope only
C. Pipe diameter
D. Building height

*Correct Answer: C. *

Rationale: The pipe diameter dictates how far the trap arm can extend before
proper venting is compromised. Larger pipes allow longer distances between
the trap and the vent.




Question 4
Which vent type is permitted to serve both the venting function and the
drainage of a single fixture in a residential bathroom?

A. Circuit vent
B. Wet vent
C. Loop vent
D. Air admittance valve

*Correct Answer: B. *

,Rationale: A wet vent serves both the venting function and drainage of a
single fixture in a residential bathroom. This is a permitted venting method
under most plumbing codes.




Question 5
What is the primary principle behind a gravity drainage system?

A. Pressure difference
B. The downward slope of pipes using gravity to move waste
C. Vacuum suction
D. Pump-assisted flow

*Correct Answer: B. *

Rationale: Gravity drainage systems rely on the downward slope of pipes to
move waste and wastewater through the system. The slope must be sufficient
to maintain adequate flow velocity.




Question 6
In a commercial building, what is the primary purpose of a vent system in
plumbing?

A. Remove waste water
B. Prevent freezing of pipes
C. Equalize pressure to prevent trap siphonage
D. Increase water pressure

*Correct Answer: C. *

Rationale: Vent systems equalize pressure in the drainage system, preventing
traps from being siphoned dry and allowing wastewater to flow efficiently.

, Question 7
Which of the following materials is NOT approved for use in a residential
cold-water supply system under the 2018 IPC?

A. PEX-a tubing
B. PVC Schedule 40
C. Copper Type L
D. CPVC

*Correct Answer: B. *

Rationale: PVC Schedule 40 is not approved for use in residential cold-water
supply systems under the 2018 IPC. PEX, copper, and CPVC are approved
materials for potable water supply.




Question 8
A plumbing fixture tailpiece connects a fixture to the:

A. Vent stack
B. Trap
C. Cleanout
D. Main sewer line

*Correct Answer: B. *

Rationale: The tailpiece carries wastewater from the fixture to its trap,
connecting the fixture outlet to the trap inlet.