AZ C-37 Plumbing Contractor Exam Questions
and Correct Answers (Verified Answers) Plus
Rationale 2027 Q&A| Instant Download Pdf
1. What is the primary function of a plumbing drainage system?
a. To supply potable water to fixtures
b. To increase water pressure throughout a building
c. To safely convey wastewater and sewage away from the building
d. To regulate the temperature of domestic hot water
Rationale: A drainage system collects and transports wastewater from
plumbing fixtures to an approved disposal system, such as a public
sewer or septic system. It relies on proper pipe sizing, slope, venting,
and connections to maintain sanitary conditions and prevent
blockages.
2. Which plumbing code is commonly used as a technical reference for
plumbing installations in Arizona?
a. National Electrical Code (NEC)
,b. International Mechanical Code (IMC) only
c. International Plumbing Code (IPC), as adopted and amended by the
applicable jurisdiction
d. International Fire Code (IFC) only
Rationale: Arizona jurisdictions adopt plumbing regulations through
applicable state and local requirements. The International Plumbing
Code is a major technical reference, but contractors must verify the
specific code edition and amendments adopted by the authority
having jurisdiction (AHJ).
3. What is the primary purpose of a plumbing trap?
a. To increase drainage velocity
b. To prevent water hammer
c. To maintain a water seal that prevents sewer gases from entering
occupied spaces
d. To prevent excessive water pressure
Rationale: A plumbing trap retains water in its curved section,
creating a barrier against sewer gases and odors. The trap must be
properly installed and protected from siphonage, evaporation, and
other conditions that could compromise its water seal.
,4. Which fitting is generally appropriate for connecting a horizontal
drainage branch to a horizontal drainage line?
a. Sanitary tee installed horizontally
b. Standard vent tee
c. Wye fitting or an approved combination wye and one-eighth bend
d. Straight coupling
Rationale: A wye or approved combination fitting provides a gradual
flow path into the drainage system. This helps wastewater enter the
main without the abrupt directional change associated with an
improperly installed sanitary tee. The fitting must be suitable for the
specific drainage configuration.
5. What is the purpose of a plumbing vent system?
a. To increase the temperature of wastewater
b. To provide additional water pressure to fixtures
c. To protect trap seals by allowing air movement and equalizing
pressure in the drainage system
d. To eliminate the need for drain cleanouts
Rationale: Plumbing vents allow air to enter and move through the
drainage system, helping prevent pressure fluctuations that could
, siphon or blow out trap seals. They also provide a pathway for sewer
gases to discharge safely outdoors in accordance with applicable code
requirements.
6. Which instrument is commonly used to measure water pressure in
a plumbing system?
a. Anemometer
b. Hydrometer
c. Pressure gauge
d. Thermocouple
Rationale: A pressure gauge measures the force exerted by water per
unit area, typically in pounds per square inch (psi). It is used to check
supply pressure, verify pressure-reducing valve performance, and
assist with system testing and troubleshooting.
7. What is the primary purpose of a pressure-reducing valve (PRV)?
a. To increase water pressure above the incoming supply pressure
b. To prevent wastewater from flowing backward
c. To reduce and regulate excessive incoming water pressure
d. To remove sediment from drinking water
and Correct Answers (Verified Answers) Plus
Rationale 2027 Q&A| Instant Download Pdf
1. What is the primary function of a plumbing drainage system?
a. To supply potable water to fixtures
b. To increase water pressure throughout a building
c. To safely convey wastewater and sewage away from the building
d. To regulate the temperature of domestic hot water
Rationale: A drainage system collects and transports wastewater from
plumbing fixtures to an approved disposal system, such as a public
sewer or septic system. It relies on proper pipe sizing, slope, venting,
and connections to maintain sanitary conditions and prevent
blockages.
2. Which plumbing code is commonly used as a technical reference for
plumbing installations in Arizona?
a. National Electrical Code (NEC)
,b. International Mechanical Code (IMC) only
c. International Plumbing Code (IPC), as adopted and amended by the
applicable jurisdiction
d. International Fire Code (IFC) only
Rationale: Arizona jurisdictions adopt plumbing regulations through
applicable state and local requirements. The International Plumbing
Code is a major technical reference, but contractors must verify the
specific code edition and amendments adopted by the authority
having jurisdiction (AHJ).
3. What is the primary purpose of a plumbing trap?
a. To increase drainage velocity
b. To prevent water hammer
c. To maintain a water seal that prevents sewer gases from entering
occupied spaces
d. To prevent excessive water pressure
Rationale: A plumbing trap retains water in its curved section,
creating a barrier against sewer gases and odors. The trap must be
properly installed and protected from siphonage, evaporation, and
other conditions that could compromise its water seal.
,4. Which fitting is generally appropriate for connecting a horizontal
drainage branch to a horizontal drainage line?
a. Sanitary tee installed horizontally
b. Standard vent tee
c. Wye fitting or an approved combination wye and one-eighth bend
d. Straight coupling
Rationale: A wye or approved combination fitting provides a gradual
flow path into the drainage system. This helps wastewater enter the
main without the abrupt directional change associated with an
improperly installed sanitary tee. The fitting must be suitable for the
specific drainage configuration.
5. What is the purpose of a plumbing vent system?
a. To increase the temperature of wastewater
b. To provide additional water pressure to fixtures
c. To protect trap seals by allowing air movement and equalizing
pressure in the drainage system
d. To eliminate the need for drain cleanouts
Rationale: Plumbing vents allow air to enter and move through the
drainage system, helping prevent pressure fluctuations that could
, siphon or blow out trap seals. They also provide a pathway for sewer
gases to discharge safely outdoors in accordance with applicable code
requirements.
6. Which instrument is commonly used to measure water pressure in
a plumbing system?
a. Anemometer
b. Hydrometer
c. Pressure gauge
d. Thermocouple
Rationale: A pressure gauge measures the force exerted by water per
unit area, typically in pounds per square inch (psi). It is used to check
supply pressure, verify pressure-reducing valve performance, and
assist with system testing and troubleshooting.
7. What is the primary purpose of a pressure-reducing valve (PRV)?
a. To increase water pressure above the incoming supply pressure
b. To prevent wastewater from flowing backward
c. To reduce and regulate excessive incoming water pressure
d. To remove sediment from drinking water
