RHODE ISLAND JOURNEYMAN PLUMBER EXAM –
PRACTICE QUESTIONS (100)
QUESTIONS WITH CERTIFIED ANSWERS &
RATIONALES
Question 1
What is the minimum vent size commonly required in Rhode
Island plumbing code?
A. 1 inch
B. 1 1/4 inch
C. 1 1/2 inch
D. 2 inches
Answer: B. 1 1/4 inch
Rationale: Rhode Island code commonly allows 1¼-inch
minimum vent sizing for individual fixtures.
Question 2
,What is the required air gap minimum for potable water
protection?
A. Same as pipe size
B. 1 inch
C. 2 times pipe diameter
D. 3 inches
Answer: C. 2 times pipe diameter
Rationale: Air gaps must be at least twice the diameter of
the supply opening to prevent back-siphonage.
Question 3
What is the purpose of a plumbing trap?
A. Increase flow
B. Store waste
C. Prevent sewer gases from entering the building
D. Increase pressure
Answer: C. Prevent sewer gases from entering the
building
Rationale: The water seal blocks harmful sewer gases.
,Question 4
What is the minimum slope for a 3-inch horizontal drain?
A. 1/16 in per ft
B. 1/8 in per ft
C. 1/4 in per ft
D. 1/2 in per ft
Answer: B. 1/8 in per ft
Rationale: Larger drains require less slope than smaller
ones to maintain velocity.
Question 5
What fixture requires the largest drainage load?
A. Lavatory
B. Shower
C. Water closet
D. Sink
, Answer: C. Water closet
Rationale: Toilets discharge the highest volume per use.
Question 6
What is the function of a backflow preventer?
A. Increase pressure
B. Prevent contamination of potable water
C. Heat water
D. Vent sewer gas
Answer: B. Prevent contamination of potable water
Rationale: Stops reverse flow into drinking water systems.
Question 7
Which material is commonly used for DWV systems?
A. Copper
B. Steel
C. PVC
D. Brass
PRACTICE QUESTIONS (100)
QUESTIONS WITH CERTIFIED ANSWERS &
RATIONALES
Question 1
What is the minimum vent size commonly required in Rhode
Island plumbing code?
A. 1 inch
B. 1 1/4 inch
C. 1 1/2 inch
D. 2 inches
Answer: B. 1 1/4 inch
Rationale: Rhode Island code commonly allows 1¼-inch
minimum vent sizing for individual fixtures.
Question 2
,What is the required air gap minimum for potable water
protection?
A. Same as pipe size
B. 1 inch
C. 2 times pipe diameter
D. 3 inches
Answer: C. 2 times pipe diameter
Rationale: Air gaps must be at least twice the diameter of
the supply opening to prevent back-siphonage.
Question 3
What is the purpose of a plumbing trap?
A. Increase flow
B. Store waste
C. Prevent sewer gases from entering the building
D. Increase pressure
Answer: C. Prevent sewer gases from entering the
building
Rationale: The water seal blocks harmful sewer gases.
,Question 4
What is the minimum slope for a 3-inch horizontal drain?
A. 1/16 in per ft
B. 1/8 in per ft
C. 1/4 in per ft
D. 1/2 in per ft
Answer: B. 1/8 in per ft
Rationale: Larger drains require less slope than smaller
ones to maintain velocity.
Question 5
What fixture requires the largest drainage load?
A. Lavatory
B. Shower
C. Water closet
D. Sink
, Answer: C. Water closet
Rationale: Toilets discharge the highest volume per use.
Question 6
What is the function of a backflow preventer?
A. Increase pressure
B. Prevent contamination of potable water
C. Heat water
D. Vent sewer gas
Answer: B. Prevent contamination of potable water
Rationale: Stops reverse flow into drinking water systems.
Question 7
Which material is commonly used for DWV systems?
A. Copper
B. Steel
C. PVC
D. Brass
