# North Carolina Inspector Level II Certification
Exams - Practice Questions
comprehensive practice questions for all three Level II certification exams. The exams are
administered through the NC# Plumbing Practice Questions
**1. What is the minimum slope required for a 3-inch horizontal drainage pipe?**
A) 1/8 inch per foot
B) 1/4 inch per foot
C) 1/2 inch per foot
D) 3/8 inch per foot
**Answer: B**
*Rationale:* Horizontal drainage pipes 3 inches or larger require a minimum slope of 1/4 inch per
foot to ensure proper drainage and prevent blockages.
**2. Which type of valve is commonly used to isolate water supply to a fixture?**
A) Check valve
B) Gate valve
C) Pressure-reducing valve
D) Vacuum breaker
**Answer: B**
*Rationale:* Gate valves allow full isolation of water to a fixture without affecting the rest of the
system.
**3. In a commercial building, which fixture requires an indirect waste connection?**
A) Lavatory
B) Dishwasher
C) Water closet
D) Shower
**Answer: B**
*Rationale:* Indirect waste connections prevent backflow from appliances like dishwashers into the
potable water system.
**4. Which type of vent is used to relieve pressure and prevent siphoning of traps?**
A) Circuit vent
B) Individual vent
, C) Stack vent
D) Relief vent
**Answer: B**
*Rationale:* An individual vent connects directly to a fixture's drain to prevent siphoning and
maintain proper trap seal.
**5. How often must a backflow preventer be tested according to NC Plumbing Code?**
A) Monthly
B) Annually
C) Every 5 years
D) Every 2 years
**Answer: B**
*Rationale:* Annual testing ensures the device is functioning properly to prevent contamination of
potable water.
**6. Which material is NOT approved for potable water piping in North Carolina?**
A) Copper
B) CPVC
C) Lead
D) PEX
**Answer: C**
*Rationale:* Lead is prohibited in potable water systems due to health hazards.
**7. What is the minimum trap seal depth for a residential lavatory?**
A) 1 inch
B) 2 inches
C) 3 inches
D) 4 inches
**Answer: B**
*Rationale:* A minimum 2-inch trap seal is required to ensure proper sealing against sewer gas.
**8. What is the required minimum diameter for a building trap?**
A) 1 inch
B) 1 1/2 inches
C) 2 inches
D) 3 inches
**Answer: C**
*Rationale:* Building traps must be at least 2 inches in diameter to handle anticipated drainage flows.
Exams - Practice Questions
comprehensive practice questions for all three Level II certification exams. The exams are
administered through the NC# Plumbing Practice Questions
**1. What is the minimum slope required for a 3-inch horizontal drainage pipe?**
A) 1/8 inch per foot
B) 1/4 inch per foot
C) 1/2 inch per foot
D) 3/8 inch per foot
**Answer: B**
*Rationale:* Horizontal drainage pipes 3 inches or larger require a minimum slope of 1/4 inch per
foot to ensure proper drainage and prevent blockages.
**2. Which type of valve is commonly used to isolate water supply to a fixture?**
A) Check valve
B) Gate valve
C) Pressure-reducing valve
D) Vacuum breaker
**Answer: B**
*Rationale:* Gate valves allow full isolation of water to a fixture without affecting the rest of the
system.
**3. In a commercial building, which fixture requires an indirect waste connection?**
A) Lavatory
B) Dishwasher
C) Water closet
D) Shower
**Answer: B**
*Rationale:* Indirect waste connections prevent backflow from appliances like dishwashers into the
potable water system.
**4. Which type of vent is used to relieve pressure and prevent siphoning of traps?**
A) Circuit vent
B) Individual vent
, C) Stack vent
D) Relief vent
**Answer: B**
*Rationale:* An individual vent connects directly to a fixture's drain to prevent siphoning and
maintain proper trap seal.
**5. How often must a backflow preventer be tested according to NC Plumbing Code?**
A) Monthly
B) Annually
C) Every 5 years
D) Every 2 years
**Answer: B**
*Rationale:* Annual testing ensures the device is functioning properly to prevent contamination of
potable water.
**6. Which material is NOT approved for potable water piping in North Carolina?**
A) Copper
B) CPVC
C) Lead
D) PEX
**Answer: C**
*Rationale:* Lead is prohibited in potable water systems due to health hazards.
**7. What is the minimum trap seal depth for a residential lavatory?**
A) 1 inch
B) 2 inches
C) 3 inches
D) 4 inches
**Answer: B**
*Rationale:* A minimum 2-inch trap seal is required to ensure proper sealing against sewer gas.
**8. What is the required minimum diameter for a building trap?**
A) 1 inch
B) 1 1/2 inches
C) 2 inches
D) 3 inches
**Answer: C**
*Rationale:* Building traps must be at least 2 inches in diameter to handle anticipated drainage flows.
