[HPC] Hawaii Plumbing Contractor Certification Review
Guide
**Question 1.** Which section of the Uniform Plumbing Code (UPC) defines the scope of
applicability for new construction versus existing installations?
A) Chapter 1 – Administration
B) Chapter 4 – Plumbing Materials
C) Chapter 7 – Water Supply and Distribution
D) Chapter 10 – Drainage Systems
Answer: A
Explanation: Chapter 1 of the UPC outlines the code’s jurisdiction, including distinctions
between new construction and existing work.
**Question 2.** In Hawaii, the Authority Having Jurisdiction (AHJ) for most plumbing permits is
typically the:
A) County Health Department
B) State Department of Labor
C) Local Building Department
D) Federal Environmental Agency
Answer: C
Explanation: Local building departments act as the AHJ, reviewing permits and conducting
inspections for plumbing projects.
**Question 3.** Which of the following piping materials is NOT approved for underground
potable water service in Hawaii under the UPC?
A) PEX‑b
B) Copper Type L
C) PVC‑SCH 40
D) ABS
Answer: D
, [HPC] Hawaii Plumbing Contractor Certification Review
Guide
Explanation: ABS is prohibited for potable water; it is only permitted for DWV applications.
**Question 4.** Water hammer in a plumbing system is primarily caused by:
A) Thermal expansion of water
B) Sudden closure of a valve
C) Improper pipe slope
D) Low water pressure
Answer: B
Explanation: Rapid valve closure creates a pressure surge known as water hammer.
**Question 5.** The phenomenon of siphonage most commonly occurs in:
A) Hot water recirculation loops
B) Drainage traps that are too far from vent stacks
C) High‑rise fire sprinkler systems
D) Pressurized gas lines
Answer: B
Explanation: Excessive distance between a trap and vent can cause the trap to be siphoned dry.
**Question 6.** When using the fixture unit method, a standard bathtub is assigned how many
water supply fixture units (WSFUs) in the UPC?
A) 1.5
B) 2.0
C) 2.5
D) 3.0
Answer: B
Explanation: The UPC lists a bathtub as 2.0 WSFUs for sizing water distribution.
, [HPC] Hawaii Plumbing Contractor Certification Review
Guide
**Question 7.** A commercial kitchen’s three‑compartment sink typically requires a minimum
of how many fixture units?
A) 4
B) 6
C) 8
D) 10
Answer: C
Explanation: Each sink compartment is 2 WSFUs, totaling 6 WSFUs; the UPC adds a 2 WSFU
allowance, resulting in 8 WSFUs.
**Question 8.** Which backflow prevention device provides the highest level of protection and
is required for connections to a public water system serving hazardous chemicals?
A) Double Check Valve Assembly (DCVA)
B) Pressure Vacuum Breaker (PVB)
C) Reduced Pressure Zone (RPZ) assembly
D) Atmospheric Vacuum Breaker (AVB)
Answer: C
Explanation: RPZ assemblies offer the most reliable protection against both backpressure and
backsiphonage.
**Question 9.** The annual testing interval for a RPZ backflow assembly in Hawaii is:
A) Every 6 months
B) Every 12 months
C) Every 24 months
D) No testing required after installation
Answer: B
, [HPC] Hawaii Plumbing Contractor Certification Review
Guide
Explanation: Hawaii’s plumbing code mandates RPZ assemblies be tested annually.
**Question 10.** Which type of water heater must be equipped with a temperature and
pressure (T&P) relief valve according to the UPC?
A) Electric tankless water heater
B) Gas‑fired storage tank water heater
C) Solar thermal collector only
D) Heat pump water heater with built‑in pressure control
Answer: B
Explanation: All storage‑type water heaters, including gas‑fired units, require a T&P valve.
**Question 11.** For a closed‑loop hydronic heating system, the expansion tank should be
installed:
A) Downstream of the T&P valve
B) At the highest point of the system
C) On the supply side before the first branch
D) In parallel with the water heater’s inlet
Answer: C
Explanation: Placing the expansion tank on the supply side allows it to absorb pressure changes
before distribution.
**Question 12.** A booster pump is most appropriate when:
A) The incoming water pressure exceeds 80 psi
B) The building’s highest fixture is more than 150 ft above the water source
C) The water heater is oversized
D) The pressure‑reducing valve is failing
Guide
**Question 1.** Which section of the Uniform Plumbing Code (UPC) defines the scope of
applicability for new construction versus existing installations?
A) Chapter 1 – Administration
B) Chapter 4 – Plumbing Materials
C) Chapter 7 – Water Supply and Distribution
D) Chapter 10 – Drainage Systems
Answer: A
Explanation: Chapter 1 of the UPC outlines the code’s jurisdiction, including distinctions
between new construction and existing work.
**Question 2.** In Hawaii, the Authority Having Jurisdiction (AHJ) for most plumbing permits is
typically the:
A) County Health Department
B) State Department of Labor
C) Local Building Department
D) Federal Environmental Agency
Answer: C
Explanation: Local building departments act as the AHJ, reviewing permits and conducting
inspections for plumbing projects.
**Question 3.** Which of the following piping materials is NOT approved for underground
potable water service in Hawaii under the UPC?
A) PEX‑b
B) Copper Type L
C) PVC‑SCH 40
D) ABS
Answer: D
, [HPC] Hawaii Plumbing Contractor Certification Review
Guide
Explanation: ABS is prohibited for potable water; it is only permitted for DWV applications.
**Question 4.** Water hammer in a plumbing system is primarily caused by:
A) Thermal expansion of water
B) Sudden closure of a valve
C) Improper pipe slope
D) Low water pressure
Answer: B
Explanation: Rapid valve closure creates a pressure surge known as water hammer.
**Question 5.** The phenomenon of siphonage most commonly occurs in:
A) Hot water recirculation loops
B) Drainage traps that are too far from vent stacks
C) High‑rise fire sprinkler systems
D) Pressurized gas lines
Answer: B
Explanation: Excessive distance between a trap and vent can cause the trap to be siphoned dry.
**Question 6.** When using the fixture unit method, a standard bathtub is assigned how many
water supply fixture units (WSFUs) in the UPC?
A) 1.5
B) 2.0
C) 2.5
D) 3.0
Answer: B
Explanation: The UPC lists a bathtub as 2.0 WSFUs for sizing water distribution.
, [HPC] Hawaii Plumbing Contractor Certification Review
Guide
**Question 7.** A commercial kitchen’s three‑compartment sink typically requires a minimum
of how many fixture units?
A) 4
B) 6
C) 8
D) 10
Answer: C
Explanation: Each sink compartment is 2 WSFUs, totaling 6 WSFUs; the UPC adds a 2 WSFU
allowance, resulting in 8 WSFUs.
**Question 8.** Which backflow prevention device provides the highest level of protection and
is required for connections to a public water system serving hazardous chemicals?
A) Double Check Valve Assembly (DCVA)
B) Pressure Vacuum Breaker (PVB)
C) Reduced Pressure Zone (RPZ) assembly
D) Atmospheric Vacuum Breaker (AVB)
Answer: C
Explanation: RPZ assemblies offer the most reliable protection against both backpressure and
backsiphonage.
**Question 9.** The annual testing interval for a RPZ backflow assembly in Hawaii is:
A) Every 6 months
B) Every 12 months
C) Every 24 months
D) No testing required after installation
Answer: B
, [HPC] Hawaii Plumbing Contractor Certification Review
Guide
Explanation: Hawaii’s plumbing code mandates RPZ assemblies be tested annually.
**Question 10.** Which type of water heater must be equipped with a temperature and
pressure (T&P) relief valve according to the UPC?
A) Electric tankless water heater
B) Gas‑fired storage tank water heater
C) Solar thermal collector only
D) Heat pump water heater with built‑in pressure control
Answer: B
Explanation: All storage‑type water heaters, including gas‑fired units, require a T&P valve.
**Question 11.** For a closed‑loop hydronic heating system, the expansion tank should be
installed:
A) Downstream of the T&P valve
B) At the highest point of the system
C) On the supply side before the first branch
D) In parallel with the water heater’s inlet
Answer: C
Explanation: Placing the expansion tank on the supply side allows it to absorb pressure changes
before distribution.
**Question 12.** A booster pump is most appropriate when:
A) The incoming water pressure exceeds 80 psi
B) The building’s highest fixture is more than 150 ft above the water source
C) The water heater is oversized
D) The pressure‑reducing valve is failing
