J3 - California Residential Plumbing Inspector Exam - 100 Questions AND CORRECT
ANSWERS GRADE A LATEST
**QUESTION 1:**
According to the California Plumbing Code, what is the minimum size for a building sewer
serving a single-family dwelling?
A) 2 inches
B) 3 inches
C) 4 inches
D) 6 inches
**ANSWER:** B
**EXPLANATION:** The California Plumbing Code requires a minimum 3-inch diameter
building sewer for single-family dwellings.
**QUESTION 2:**
What is the maximum horizontal distance a vent pipe can run from a trap weir without
additional venting?
A) 2 feet
B) 3 feet
C) 5 feet
D) 6 feet
**ANSWER:** C
**EXPLANATION:** The trap weir to vent distance cannot exceed 5 feet horizontally for a
1¼-inch or smaller pipe, or 6 feet for a 1½-inch or larger pipe.
,**QUESTION 3:**
Which of the following requires an air gap for backflow prevention?
A) Water closet
B) Lavatory
C) Kitchen sink
D) Hose bib with chemical dispenser
**ANSWER:** D
**EXPLANATION:** Hose bibs with chemical dispensers require an air gap (the highest
level of backflow protection) due to potential contamination.
**QUESTION 4:**
What is the minimum required slope for a 4-inch diameter horizontal drainage pipe?
A) 1/8 inch per foot
B) 1/4 inch per foot
C) 1/2 inch per foot
D) 1 inch per foot
**ANSWER:** B
**EXPLANATION:** A 4-inch diameter drainage pipe requires a minimum slope of 1/4 inch
per foot (2% grade).
**QUESTION 5:**
According to California energy efficiency requirements, what is the maximum flow rate for a
residential showerhead?
A) 1.5 gpm
B) 2.0 gpm
,C) 2.5 gpm
D) 3.0 gpm
**ANSWER:** C
**EXPLANATION:** California energy efficiency standards limit showerheads to maximum
2.5 gallons per minute.
**QUESTION 6:**
What is the minimum required clearance in front of a water heater?
A) 12 inches
B) 18 inches
C) 24 inches
D) 36 inches
**ANSWER:** C
**EXPLANATION:** Water heaters require minimum 24-inch clearance in front for servicing
and inspection access.
**QUESTION 7:**
Which type of pipe is NOT approved for underground water service in California?
A) Copper Type K
B) CPVC
C) PEX
D) Galvanized steel
**ANSWER:** D
, **EXPLANATION:** Galvanized steel is not approved for underground water service due to
corrosion concerns; copper, CPVC, and PEX are approved.
**QUESTION 8:**
What is the maximum allowable length for a 1½-inch trap arm?
A) 3 feet 6 inches
B) 5 feet
C) 6 feet
D) 8 feet
**ANSWER:** A
**EXPLANATION:** For a 1½-inch trap arm, the maximum distance from trap weir to vent is
3 feet 6 inches.
**QUESTION 9:**
Which fixture requires the largest drain size?
A) Bathroom lavatory
B) Kitchen sink
C) Bathtub
D) Water closet
**ANSWER:** D
**EXPLANATION:** Water closets require minimum 3-inch drain pipes, while other fixtures
typically use 1¼-inch to 2-inch drains.
**QUESTION 10:**
What is the minimum required water pressure at fixtures?
ANSWERS GRADE A LATEST
**QUESTION 1:**
According to the California Plumbing Code, what is the minimum size for a building sewer
serving a single-family dwelling?
A) 2 inches
B) 3 inches
C) 4 inches
D) 6 inches
**ANSWER:** B
**EXPLANATION:** The California Plumbing Code requires a minimum 3-inch diameter
building sewer for single-family dwellings.
**QUESTION 2:**
What is the maximum horizontal distance a vent pipe can run from a trap weir without
additional venting?
A) 2 feet
B) 3 feet
C) 5 feet
D) 6 feet
**ANSWER:** C
**EXPLANATION:** The trap weir to vent distance cannot exceed 5 feet horizontally for a
1¼-inch or smaller pipe, or 6 feet for a 1½-inch or larger pipe.
,**QUESTION 3:**
Which of the following requires an air gap for backflow prevention?
A) Water closet
B) Lavatory
C) Kitchen sink
D) Hose bib with chemical dispenser
**ANSWER:** D
**EXPLANATION:** Hose bibs with chemical dispensers require an air gap (the highest
level of backflow protection) due to potential contamination.
**QUESTION 4:**
What is the minimum required slope for a 4-inch diameter horizontal drainage pipe?
A) 1/8 inch per foot
B) 1/4 inch per foot
C) 1/2 inch per foot
D) 1 inch per foot
**ANSWER:** B
**EXPLANATION:** A 4-inch diameter drainage pipe requires a minimum slope of 1/4 inch
per foot (2% grade).
**QUESTION 5:**
According to California energy efficiency requirements, what is the maximum flow rate for a
residential showerhead?
A) 1.5 gpm
B) 2.0 gpm
,C) 2.5 gpm
D) 3.0 gpm
**ANSWER:** C
**EXPLANATION:** California energy efficiency standards limit showerheads to maximum
2.5 gallons per minute.
**QUESTION 6:**
What is the minimum required clearance in front of a water heater?
A) 12 inches
B) 18 inches
C) 24 inches
D) 36 inches
**ANSWER:** C
**EXPLANATION:** Water heaters require minimum 24-inch clearance in front for servicing
and inspection access.
**QUESTION 7:**
Which type of pipe is NOT approved for underground water service in California?
A) Copper Type K
B) CPVC
C) PEX
D) Galvanized steel
**ANSWER:** D
, **EXPLANATION:** Galvanized steel is not approved for underground water service due to
corrosion concerns; copper, CPVC, and PEX are approved.
**QUESTION 8:**
What is the maximum allowable length for a 1½-inch trap arm?
A) 3 feet 6 inches
B) 5 feet
C) 6 feet
D) 8 feet
**ANSWER:** A
**EXPLANATION:** For a 1½-inch trap arm, the maximum distance from trap weir to vent is
3 feet 6 inches.
**QUESTION 9:**
Which fixture requires the largest drain size?
A) Bathroom lavatory
B) Kitchen sink
C) Bathtub
D) Water closet
**ANSWER:** D
**EXPLANATION:** Water closets require minimum 3-inch drain pipes, while other fixtures
typically use 1¼-inch to 2-inch drains.
**QUESTION 10:**
What is the minimum required water pressure at fixtures?
