UTAH PLUMBING CONTRACTOR EXAM – QUESTIONS AND ANSWERS | VERIFIED AND WELL
DETAILED ANSWERS | PLUS RATIONALES | GUARANTEED PASS | LATEST EXAM UPDATE
*Core Domains*
*Drainage, Waste, and Vent Systems*
*Water Supply and Distribution*
*Backflow Prevention*
*Fixtures and Interceptors*
*Fuel Gas Systems*
*Administrative Policies*
*Utah-Specific Code Amendments*
*Safety and OSHA Regulations*
*Introduction*
*This examination assessment is designed to evaluate the comprehensive technical
proficiency and regulatory knowledge required of a licensed Plumbing Contractor in the
State of Utah. The assessment covers a broad spectrum of competencies, including the
design, installation, and maintenance of various piping systems in accordance with current
state-adopted codes. Through a combination of theoretical multiple-choice questions and
complex scenario-based problems, candidates are tested on their ability to apply practical
plumbing solutions while ensuring public health and safety. Emphasis is placed on real-world
decision-making, critical thinking, and strict adherence to legal and ethical standards within
the construction industry.*
**SECTION ONE**
1. What is the minimum required size for a building sewer in a residential application?
A. 2 inches B. 3 inches C. 4 inches D. 6 inches
B. 3 inches
, Explanation: Per standard plumbing code requirements adopted in Utah, the building
sewer must be at least 3 inches in diameter to adequately handle the discharge from a
standard residential building drain.
2. A plumbing contractor is installing a water heater in a garage. At what height must
the ignition source be located above the floor?
A. 6 inches B. 12 inches C. 18 inches D. 24 inches
C. 18 inches
Explanation: To prevent the ignition of flammable vapors that may settle near the floor,
the International Plumbing Code (IPC) requires ignition sources to be at least 18 inches
above the garage floor.
3. Which of the following is considered a "critical level" in backflow prevention?
A. The highest point of the piping system B. The point where the pressure is at its maximum
C. The point at which the vacuum breaker is installed D. The elevation at which the backflow
preventer's discharge begins
C. The point at which the vacuum breaker is installed
Explanation: The critical level (CL) is the point on a backflow prevention device that
determines the minimum elevation at which the device can be installed above the flood
level rim of the fixture it serves.
4. When testing a DWV system with air, what is the required pressure that must be
maintained for at least 15 minutes?
A. 3 psi B. 5 psi C. 10 psi D. 15 psi
B. 5 psi
Explanation: Standard code requires an air test for Drainage, Waste, and Vent (DWV)
systems to be performed at a minimum of 5 psi to ensure there are no leaks in the piping or
joints.
5. What is the maximum distance a manual gas shutoff valve can be located from the
appliance it serves?
A. 3 feet B. 6 feet C. 10 feet D. 12 feet
B. 6 feet
Explanation: For safety and ease of access during maintenance or emergencies, gas
shutoff valves must be located in the same room and within 6 feet of the appliance.
6. A kitchen sink tailpiece shall be no less than how many inches in diameter?
,A. 1-1/4 inches B. 1-1/2 inches C. 2 inches D. 2-1/2 inches
B. 1-1/2 inches
Explanation: The standard minimum size for a kitchen sink drain tailpiece is 1-1/2 inches
to ensure proper drainage flow and reduce the risk of clogs.
7. Which material is prohibited for use as an underground water service pipe?
A. Copper type K B. Ductile iron C. PVC Schedule 80 D. Solder-joint copper (Type M)
D. Solder-joint copper (Type M)
Explanation: Type M copper is typically too thin for underground burial due to soil stress
and corrosion risks; Type K or L is generally required for underground water service.
8. What is the minimum slope required for a horizontal drain pipe with a diameter of 3
inches or less?
A. 1/8 inch per foot B. 1/4 inch per foot C. 1/2 inch per foot D. 1 inch per foot
B. 1/4 inch per foot
Explanation: For pipes 3 inches or smaller, a 1/4 inch per foot slope is mandatory to
maintain the velocity necessary for scouring and preventing solids from settling.
9. In a scenario where a water closet is being installed, what is the minimum clearance
required from the center of the fixture to any side wall?
A. 12 inches B. 15 inches C. 18 inches D. 21 inches
B. 15 inches
Explanation: Accessibility and comfort standards dictate a minimum of 15 inches from
the center of the water closet to any side wall or partition.
10. A "vent stack" is primarily defined as:
A. A vent that serves only one fixture B. A vertical vent pipe installed primarily for the
purpose of providing circulation of air to and from any part of the drainage system C. The
highest point of a soil stack D. A horizontal vent pipe connecting multiple fixtures
B. A vertical vent pipe installed primarily for the purpose of providing circulation of air to
and from any part of the drainage system
Explanation: A vent stack is a vertical pipe specifically designed to provide air circulation
throughout the drainage system to protect trap seals.
11. What is the maximum temperature allowed for water discharged into a public sewer
system?
, A. 110°F B. 120°F C. 140°F D. 160°F
C. 140°F
Explanation: To prevent damage to the sewer infrastructure and biological treatment
processes, discharge temperatures must not exceed 140°F.
12. Which device is used to prevent the collapse of a storage tank caused by a vacuum?
A. Pressure relief valve B. Check valve C. Vacuum breaker valve D. Gate valve
C. Vacuum breaker valve
Explanation: A vacuum breaker valve allows air into the system when a vacuum is
sensed, equalizing pressure and preventing the tank or piping from collapsing.
13. How often must a backflow prevention assembly be tested in Utah?
A. Every 6 months B. Annually C. Every 2 years D. Only upon installation
B. Annually
Explanation: Utah state regulations require that all backflow prevention assemblies be
tested by a certified technician at least once a year to ensure public water safety.
14. What is the minimum size of a vent for a sewage ejector pump?
A. 1-1/4 inches B. 1-1/2 inches C. 2 inches D. 3 inches
C. 2 inches
Explanation: Because sewage ejectors move large volumes of air and waste quickly, a
minimum 2-inch vent is required to prevent pressure fluctuations that could blow out fixture
traps.
15. What is the maximum length of a 2-inch diameter trap arm?
A. 4 feet B. 5 feet C. 6 feet D. 8 feet
D. 8 feet
Explanation: According to the trap arm distance tables, a 2-inch pipe allows for a
maximum distance of 8 feet between the trap and the vent.
16. Which of the following is a prohibited trap?
A. P-trap B. Swivel trap C. S-trap D. Deep seal trap
C. S-trap
DETAILED ANSWERS | PLUS RATIONALES | GUARANTEED PASS | LATEST EXAM UPDATE
*Core Domains*
*Drainage, Waste, and Vent Systems*
*Water Supply and Distribution*
*Backflow Prevention*
*Fixtures and Interceptors*
*Fuel Gas Systems*
*Administrative Policies*
*Utah-Specific Code Amendments*
*Safety and OSHA Regulations*
*Introduction*
*This examination assessment is designed to evaluate the comprehensive technical
proficiency and regulatory knowledge required of a licensed Plumbing Contractor in the
State of Utah. The assessment covers a broad spectrum of competencies, including the
design, installation, and maintenance of various piping systems in accordance with current
state-adopted codes. Through a combination of theoretical multiple-choice questions and
complex scenario-based problems, candidates are tested on their ability to apply practical
plumbing solutions while ensuring public health and safety. Emphasis is placed on real-world
decision-making, critical thinking, and strict adherence to legal and ethical standards within
the construction industry.*
**SECTION ONE**
1. What is the minimum required size for a building sewer in a residential application?
A. 2 inches B. 3 inches C. 4 inches D. 6 inches
B. 3 inches
, Explanation: Per standard plumbing code requirements adopted in Utah, the building
sewer must be at least 3 inches in diameter to adequately handle the discharge from a
standard residential building drain.
2. A plumbing contractor is installing a water heater in a garage. At what height must
the ignition source be located above the floor?
A. 6 inches B. 12 inches C. 18 inches D. 24 inches
C. 18 inches
Explanation: To prevent the ignition of flammable vapors that may settle near the floor,
the International Plumbing Code (IPC) requires ignition sources to be at least 18 inches
above the garage floor.
3. Which of the following is considered a "critical level" in backflow prevention?
A. The highest point of the piping system B. The point where the pressure is at its maximum
C. The point at which the vacuum breaker is installed D. The elevation at which the backflow
preventer's discharge begins
C. The point at which the vacuum breaker is installed
Explanation: The critical level (CL) is the point on a backflow prevention device that
determines the minimum elevation at which the device can be installed above the flood
level rim of the fixture it serves.
4. When testing a DWV system with air, what is the required pressure that must be
maintained for at least 15 minutes?
A. 3 psi B. 5 psi C. 10 psi D. 15 psi
B. 5 psi
Explanation: Standard code requires an air test for Drainage, Waste, and Vent (DWV)
systems to be performed at a minimum of 5 psi to ensure there are no leaks in the piping or
joints.
5. What is the maximum distance a manual gas shutoff valve can be located from the
appliance it serves?
A. 3 feet B. 6 feet C. 10 feet D. 12 feet
B. 6 feet
Explanation: For safety and ease of access during maintenance or emergencies, gas
shutoff valves must be located in the same room and within 6 feet of the appliance.
6. A kitchen sink tailpiece shall be no less than how many inches in diameter?
,A. 1-1/4 inches B. 1-1/2 inches C. 2 inches D. 2-1/2 inches
B. 1-1/2 inches
Explanation: The standard minimum size for a kitchen sink drain tailpiece is 1-1/2 inches
to ensure proper drainage flow and reduce the risk of clogs.
7. Which material is prohibited for use as an underground water service pipe?
A. Copper type K B. Ductile iron C. PVC Schedule 80 D. Solder-joint copper (Type M)
D. Solder-joint copper (Type M)
Explanation: Type M copper is typically too thin for underground burial due to soil stress
and corrosion risks; Type K or L is generally required for underground water service.
8. What is the minimum slope required for a horizontal drain pipe with a diameter of 3
inches or less?
A. 1/8 inch per foot B. 1/4 inch per foot C. 1/2 inch per foot D. 1 inch per foot
B. 1/4 inch per foot
Explanation: For pipes 3 inches or smaller, a 1/4 inch per foot slope is mandatory to
maintain the velocity necessary for scouring and preventing solids from settling.
9. In a scenario where a water closet is being installed, what is the minimum clearance
required from the center of the fixture to any side wall?
A. 12 inches B. 15 inches C. 18 inches D. 21 inches
B. 15 inches
Explanation: Accessibility and comfort standards dictate a minimum of 15 inches from
the center of the water closet to any side wall or partition.
10. A "vent stack" is primarily defined as:
A. A vent that serves only one fixture B. A vertical vent pipe installed primarily for the
purpose of providing circulation of air to and from any part of the drainage system C. The
highest point of a soil stack D. A horizontal vent pipe connecting multiple fixtures
B. A vertical vent pipe installed primarily for the purpose of providing circulation of air to
and from any part of the drainage system
Explanation: A vent stack is a vertical pipe specifically designed to provide air circulation
throughout the drainage system to protect trap seals.
11. What is the maximum temperature allowed for water discharged into a public sewer
system?
, A. 110°F B. 120°F C. 140°F D. 160°F
C. 140°F
Explanation: To prevent damage to the sewer infrastructure and biological treatment
processes, discharge temperatures must not exceed 140°F.
12. Which device is used to prevent the collapse of a storage tank caused by a vacuum?
A. Pressure relief valve B. Check valve C. Vacuum breaker valve D. Gate valve
C. Vacuum breaker valve
Explanation: A vacuum breaker valve allows air into the system when a vacuum is
sensed, equalizing pressure and preventing the tank or piping from collapsing.
13. How often must a backflow prevention assembly be tested in Utah?
A. Every 6 months B. Annually C. Every 2 years D. Only upon installation
B. Annually
Explanation: Utah state regulations require that all backflow prevention assemblies be
tested by a certified technician at least once a year to ensure public water safety.
14. What is the minimum size of a vent for a sewage ejector pump?
A. 1-1/4 inches B. 1-1/2 inches C. 2 inches D. 3 inches
C. 2 inches
Explanation: Because sewage ejectors move large volumes of air and waste quickly, a
minimum 2-inch vent is required to prevent pressure fluctuations that could blow out fixture
traps.
15. What is the maximum length of a 2-inch diameter trap arm?
A. 4 feet B. 5 feet C. 6 feet D. 8 feet
D. 8 feet
Explanation: According to the trap arm distance tables, a 2-inch pipe allows for a
maximum distance of 8 feet between the trap and the vent.
16. Which of the following is a prohibited trap?
A. P-trap B. Swivel trap C. S-trap D. Deep seal trap
C. S-trap
