Florida Plumbing Contractor Licensing Exam Test
Questions And Correct Answers (Verified Answers)
Plus Rationales 2025/2026 Q&A | Instant
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1. Which of the following is the primary purpose of a plumbing vent system?
A. To supply water to fixtures
B. To remove wastewater from the building
C. To prevent the siphoning of water from traps
D. To provide water pressure to fixtures
Rationale: Vent systems maintain atmospheric pressure in the drainage
system, preventing traps from losing their water seal.
2. What is the minimum pipe size for a building sewer in a residential
property?
A. 2 inches
B. 3 inches
C. 4 inches
D. 6 inches
Rationale: Florida Plumbing Code requires a minimum of 4 inches for a
building sewer to accommodate residential wastewater flow.
3. What is the maximum horizontal distance a trap can be located from the
vent?
, A. 2 feet
B. 3 feet
C. 5 feet
D. 10 feet
Rationale: The Florida Plumbing Code limits the distance between a trap
and its vent to 5 feet for typical residential fixtures to prevent trap
siphoning.
4. Which type of backflow prevention device is required for a potable water
connection to a lawn irrigation system?
A. Air gap
B. Vacuum breaker
C. Reduced pressure principle assembly
D. Double check valve
Rationale: Lawn irrigation systems require a reduced pressure principle
assembly to prevent contaminants from entering the potable water
supply.
5. What is the minimum slope required for a 3-inch horizontal drain pipe?
A. 1/8 inch per foot
B. 1/4 inch per foot
C. 1/8 inch per foot
D. 1/2 inch per foot
Rationale: A 3-inch horizontal drain must have a minimum slope of 1/8
inch per foot to ensure proper gravity flow.
,6. Which type of pipe is commonly used for underground potable water
service in Florida?
A. PVC Schedule 40
B. Copper Type K
C. CPVC
D. ABS
Rationale: Copper Type K is preferred for underground water service due
to its durability and resistance to corrosion.
7. What is the minimum size of a vent pipe for a single fixture with a 1.5-inch
trap?
A. 1 inch
B. 1.25 inches
C. 1.5 inches
D. 2 inches
Rationale: The vent pipe must be at least the same diameter as the fixture
trap to allow adequate air circulation.
8. How often must a backflow prevention device for a commercial building be
tested?
A. Annually
B. Every 2 years
C. Every year
D. Every 5 years
Rationale: Florida law requires annual testing of backflow prevention
devices to ensure functionality.
, 9. Which of the following is the maximum allowable water temperature for a
residential shower?
A. 110°F
B. 120°F
C. 120°F
D. 130°F
Rationale: Florida Plumbing Code limits residential shower temperature to
120°F to prevent scalding.
10.When installing a water heater, what is the minimum clearance required
from combustible materials?
A. 6 inches
B. 12 inches
C. 2 inches
D. 18 inches
Rationale: Gas water heaters must have a minimum 2-inch clearance from
combustible surfaces for safety.
11.What type of pipe is prohibited for potable water supply in Florida?
A. CPVC
B. PVC Schedule 40
C. Copper Type L
D. Lead
Rationale: Lead pipe is banned for potable water due to toxicity risks.
12.Which fixture requires an air gap for its drain connection?
A. Bathroom sink
Questions And Correct Answers (Verified Answers)
Plus Rationales 2025/2026 Q&A | Instant
Download Pdf
1. Which of the following is the primary purpose of a plumbing vent system?
A. To supply water to fixtures
B. To remove wastewater from the building
C. To prevent the siphoning of water from traps
D. To provide water pressure to fixtures
Rationale: Vent systems maintain atmospheric pressure in the drainage
system, preventing traps from losing their water seal.
2. What is the minimum pipe size for a building sewer in a residential
property?
A. 2 inches
B. 3 inches
C. 4 inches
D. 6 inches
Rationale: Florida Plumbing Code requires a minimum of 4 inches for a
building sewer to accommodate residential wastewater flow.
3. What is the maximum horizontal distance a trap can be located from the
vent?
, A. 2 feet
B. 3 feet
C. 5 feet
D. 10 feet
Rationale: The Florida Plumbing Code limits the distance between a trap
and its vent to 5 feet for typical residential fixtures to prevent trap
siphoning.
4. Which type of backflow prevention device is required for a potable water
connection to a lawn irrigation system?
A. Air gap
B. Vacuum breaker
C. Reduced pressure principle assembly
D. Double check valve
Rationale: Lawn irrigation systems require a reduced pressure principle
assembly to prevent contaminants from entering the potable water
supply.
5. What is the minimum slope required for a 3-inch horizontal drain pipe?
A. 1/8 inch per foot
B. 1/4 inch per foot
C. 1/8 inch per foot
D. 1/2 inch per foot
Rationale: A 3-inch horizontal drain must have a minimum slope of 1/8
inch per foot to ensure proper gravity flow.
,6. Which type of pipe is commonly used for underground potable water
service in Florida?
A. PVC Schedule 40
B. Copper Type K
C. CPVC
D. ABS
Rationale: Copper Type K is preferred for underground water service due
to its durability and resistance to corrosion.
7. What is the minimum size of a vent pipe for a single fixture with a 1.5-inch
trap?
A. 1 inch
B. 1.25 inches
C. 1.5 inches
D. 2 inches
Rationale: The vent pipe must be at least the same diameter as the fixture
trap to allow adequate air circulation.
8. How often must a backflow prevention device for a commercial building be
tested?
A. Annually
B. Every 2 years
C. Every year
D. Every 5 years
Rationale: Florida law requires annual testing of backflow prevention
devices to ensure functionality.
, 9. Which of the following is the maximum allowable water temperature for a
residential shower?
A. 110°F
B. 120°F
C. 120°F
D. 130°F
Rationale: Florida Plumbing Code limits residential shower temperature to
120°F to prevent scalding.
10.When installing a water heater, what is the minimum clearance required
from combustible materials?
A. 6 inches
B. 12 inches
C. 2 inches
D. 18 inches
Rationale: Gas water heaters must have a minimum 2-inch clearance from
combustible surfaces for safety.
11.What type of pipe is prohibited for potable water supply in Florida?
A. CPVC
B. PVC Schedule 40
C. Copper Type L
D. Lead
Rationale: Lead pipe is banned for potable water due to toxicity risks.
12.Which fixture requires an air gap for its drain connection?
A. Bathroom sink
