1|Page
National Plumbing Code of Canada Newest Exam
Preparation With Complete Questions And Correct Answers
With Rationales Already Graded A+ Brand New Version!!
QUESTION 1
Every fixture shall have what surface requirements?
A) A smooth, hard, corrosion-resistant surface free of flaws and
blemishes that may interfere with cleaning
B) A textured surface to prevent slipping
C) A painted or coated surface for aesthetic purposes
D) A porous surface to allow for water absorption
Answer: A) A smooth, hard, corrosion-resistant surface free of flaws and
blemishes that may interfere with cleaning
Explanation: The National Plumbing Code requires that all fixtures have
surfaces that are smooth, hard, and corrosion-resistant. This ensures
proper hygiene, ease of cleaning, and durability. Flaws and blemishes
can harbor bacteria and make cleaning difficult, compromising public
health and safety.
QUESTION 2
How many shower heads may be served by a single shower drain?
,2|Page
A) 4
B) 6
C) 8
D) 10
Answer: B) 6
Explanation: The NPC explicitly limits the number of shower heads that
can be served by a single shower drain to six. This restriction ensures
adequate drainage capacity and prevents flooding or backup issues in
multi-head shower installations.
QUESTION 3
What is the minimum vertical distance required between a fixture
outlet and the trap weir for a fixture trap?
A) 50 mm
B) 75 mm
C) 100 mm
D) 150 mm
Answer: C) 100 mm
Explanation: The code mandates a minimum vertical distance of 100
mm between the fixture outlet and the trap weir. This distance ensures
that the trap maintains its seal and prevents siphoning, while also
allowing for proper flow dynamics and preventing solids from
accumulating in the trap.
,3|Page
QUESTION 4
What is the maximum allowable temperature for hot water delivered to
a public bathing facility?
A) 38 degrees Celsius
B) 43 degrees Celsius
C) 49 degrees Celsius
D) 55 degrees Celsius
Answer: C) 49 degrees Celsius
Explanation: To prevent scalding injuries in public bathing facilities, the
NPC sets the maximum hot water delivery temperature at 49 degrees
Celsius. This temperature is considered safe for human contact while
still providing adequate warmth for bathing purposes.
QUESTION 5
Which type of pipe joint is specifically prohibited for use in drainage
systems?
A) Solvent-cemented joints
B) Mechanical joints
C) Lead and oakum joints
D) Threaded joints
Answer: C) Lead and oakum joints
Explanation: Lead and oakum joints are prohibited in drainage systems
because they can allow for infiltration and exfiltration, and the lead
, 4|Page
content poses health and environmental hazards. Modern codes favor
more reliable and safer jointing methods.
QUESTION 6
What is the required grade for a building sewer pipe with a diameter of
100 mm?
A) 0.5 percent
B) 1.0 percent
C) 2.0 percent
D) 3.0 percent
Answer: C) 2.0 percent
Explanation: For a 100 mm building sewer, the NPC requires a minimum
grade of 2.0 percent. This slope ensures self-cleaning velocities are
maintained, preventing solids from settling and causing blockages
within the sewer line.
QUESTION 7
How often must a backflow prevention device that is testable be
inspected and tested?
A) Annually
B) Every six months
C) Every two years
D) At the time of installation only
Answer: A) Annually
National Plumbing Code of Canada Newest Exam
Preparation With Complete Questions And Correct Answers
With Rationales Already Graded A+ Brand New Version!!
QUESTION 1
Every fixture shall have what surface requirements?
A) A smooth, hard, corrosion-resistant surface free of flaws and
blemishes that may interfere with cleaning
B) A textured surface to prevent slipping
C) A painted or coated surface for aesthetic purposes
D) A porous surface to allow for water absorption
Answer: A) A smooth, hard, corrosion-resistant surface free of flaws and
blemishes that may interfere with cleaning
Explanation: The National Plumbing Code requires that all fixtures have
surfaces that are smooth, hard, and corrosion-resistant. This ensures
proper hygiene, ease of cleaning, and durability. Flaws and blemishes
can harbor bacteria and make cleaning difficult, compromising public
health and safety.
QUESTION 2
How many shower heads may be served by a single shower drain?
,2|Page
A) 4
B) 6
C) 8
D) 10
Answer: B) 6
Explanation: The NPC explicitly limits the number of shower heads that
can be served by a single shower drain to six. This restriction ensures
adequate drainage capacity and prevents flooding or backup issues in
multi-head shower installations.
QUESTION 3
What is the minimum vertical distance required between a fixture
outlet and the trap weir for a fixture trap?
A) 50 mm
B) 75 mm
C) 100 mm
D) 150 mm
Answer: C) 100 mm
Explanation: The code mandates a minimum vertical distance of 100
mm between the fixture outlet and the trap weir. This distance ensures
that the trap maintains its seal and prevents siphoning, while also
allowing for proper flow dynamics and preventing solids from
accumulating in the trap.
,3|Page
QUESTION 4
What is the maximum allowable temperature for hot water delivered to
a public bathing facility?
A) 38 degrees Celsius
B) 43 degrees Celsius
C) 49 degrees Celsius
D) 55 degrees Celsius
Answer: C) 49 degrees Celsius
Explanation: To prevent scalding injuries in public bathing facilities, the
NPC sets the maximum hot water delivery temperature at 49 degrees
Celsius. This temperature is considered safe for human contact while
still providing adequate warmth for bathing purposes.
QUESTION 5
Which type of pipe joint is specifically prohibited for use in drainage
systems?
A) Solvent-cemented joints
B) Mechanical joints
C) Lead and oakum joints
D) Threaded joints
Answer: C) Lead and oakum joints
Explanation: Lead and oakum joints are prohibited in drainage systems
because they can allow for infiltration and exfiltration, and the lead
, 4|Page
content poses health and environmental hazards. Modern codes favor
more reliable and safer jointing methods.
QUESTION 6
What is the required grade for a building sewer pipe with a diameter of
100 mm?
A) 0.5 percent
B) 1.0 percent
C) 2.0 percent
D) 3.0 percent
Answer: C) 2.0 percent
Explanation: For a 100 mm building sewer, the NPC requires a minimum
grade of 2.0 percent. This slope ensures self-cleaning velocities are
maintained, preventing solids from settling and causing blockages
within the sewer line.
QUESTION 7
How often must a backflow prevention device that is testable be
inspected and tested?
A) Annually
B) Every six months
C) Every two years
D) At the time of installation only
Answer: A) Annually
