California Plumbing Contractor Exam
Questions And Correct Answers (Verified
Answers) Plus Rationales 2025/2026 Q&A |
Instant Download Pdf
1. What is the minimum depth for a building sewer installed below a paved
surface?
A. 6 inches
B. 12 inches
C. 18 inches
D. 24 inches
Building sewers must be at least 18 inches deep under paved areas to protect
against surface loads.
2. According to the California Plumbing Code, how much slope is required for
a 3-inch horizontal drain?
A. 1/16 inch per foot
B. 1/8 inch per foot
C. 1/4 inch per foot
D. 1/2 inch per foot
A 3-inch horizontal drain requires a slope of 1/4 inch per foot to ensure proper
flow.
, 3. What material is prohibited for use in potable water systems?
A. CPVC
B. PEX
C. Type L copper
D. Lead
Lead is banned in potable water systems due to its toxicity.
4. The water pressure in a building should not exceed:
A. 40 psi
B. 60 psi
C. 75 psi
D. 80 psi
Pressures above 80 psi can damage fixtures and appliances; pressure-reducing
valves are required if exceeded.
5. A trap seal should be at least:
A. 1/2 inch
B. 1 inch
C. 2 inches
D. 4 inches
The standard minimum trap seal depth is 2 inches to prevent sewer gases from
entering the building.
6. What type of backflow prevention device is required on a lawn irrigation
system?
, A. Air gap
B. Pressure vacuum breaker
C. Check valve
D. Swing check
Lawn irrigation requires a pressure vacuum breaker to prevent contaminated
water from back-siphoning.
7. What is the correct pipe slope for a horizontal drain less than 3 inches in
diameter?
A. 1/16 inch per foot
B. 1/4 inch per foot
C. 1/2 inch per foot
D. 3/8 inch per foot
Smaller drains need a greater slope to maintain velocity and prevent clogs.
8. What fitting is used to join two pipes at a 90-degree angle?
A. Wye
B. Sanitary tee
C. Coupling
D. Elbow
Elbows are designed specifically for making 90-degree turns.
9. Which document governs licensing and classification for plumbing
contractors in California?
A. Title 24
B. California Contractors License Law
C. OSHA standards
Questions And Correct Answers (Verified
Answers) Plus Rationales 2025/2026 Q&A |
Instant Download Pdf
1. What is the minimum depth for a building sewer installed below a paved
surface?
A. 6 inches
B. 12 inches
C. 18 inches
D. 24 inches
Building sewers must be at least 18 inches deep under paved areas to protect
against surface loads.
2. According to the California Plumbing Code, how much slope is required for
a 3-inch horizontal drain?
A. 1/16 inch per foot
B. 1/8 inch per foot
C. 1/4 inch per foot
D. 1/2 inch per foot
A 3-inch horizontal drain requires a slope of 1/4 inch per foot to ensure proper
flow.
, 3. What material is prohibited for use in potable water systems?
A. CPVC
B. PEX
C. Type L copper
D. Lead
Lead is banned in potable water systems due to its toxicity.
4. The water pressure in a building should not exceed:
A. 40 psi
B. 60 psi
C. 75 psi
D. 80 psi
Pressures above 80 psi can damage fixtures and appliances; pressure-reducing
valves are required if exceeded.
5. A trap seal should be at least:
A. 1/2 inch
B. 1 inch
C. 2 inches
D. 4 inches
The standard minimum trap seal depth is 2 inches to prevent sewer gases from
entering the building.
6. What type of backflow prevention device is required on a lawn irrigation
system?
, A. Air gap
B. Pressure vacuum breaker
C. Check valve
D. Swing check
Lawn irrigation requires a pressure vacuum breaker to prevent contaminated
water from back-siphoning.
7. What is the correct pipe slope for a horizontal drain less than 3 inches in
diameter?
A. 1/16 inch per foot
B. 1/4 inch per foot
C. 1/2 inch per foot
D. 3/8 inch per foot
Smaller drains need a greater slope to maintain velocity and prevent clogs.
8. What fitting is used to join two pipes at a 90-degree angle?
A. Wye
B. Sanitary tee
C. Coupling
D. Elbow
Elbows are designed specifically for making 90-degree turns.
9. Which document governs licensing and classification for plumbing
contractors in California?
A. Title 24
B. California Contractors License Law
C. OSHA standards
