ALBERTA PLUMBER APPRENTICESHIP CERTIFICATION EXAM (THIRD
PERIOD) | Latest Update 2026/2027 | 200 Practice Questions and
Verified Answers | Complete Q&A Guide | A+ Graded
SECTION 1: DRAINAGE, WASTE, AND VENT (DWV) SYSTEMS
1. What is the minimum slope for a 4inch (100 mm) horizontal drainage pipe?
A) 1/8 inch per foot (1:96)
B) 1/4 inch per foot (1:48)
C) 1/2 inch per foot (1:24)
D) 3/4 inch per foot (1:16)
Answer: A) 1/8 inch per foot (1:96)
Explanation: The National Plumbing Code of Canada (NPC) requires a minimum slope of 1/8 inch per
foot (or 1:96) for pipes 4 inches (100 mm) and larger. For pipes 3 inches (75 mm) and smaller, the
minimum slope is 1/4 inch per foot (1:48).
2. The maximum number of fixture units allowed on a 4inch (100 mm) building drain with a slope of 1/8
inch per foot is:
A) 180 FU
B) 216 FU
C) 360 FU
D) 500 FU
Answer: B) 216 FU
,Explanation: According to NPC tables, a 4inch (100 mm) building drain at 1/8 inch per foot slope can
carry a maximum of 216 fixture units. At 1/4 inch per foot slope, the capacity increases to 432 fixture
units.
3. The minimum size of a building sewer (service line) for a singlefamily dwelling is:
A) 3 inches (75 mm)
B) 4 inches (100 mm)
C) 6 inches (150 mm)
D) 8 inches (200 mm)
Answer: B) 4 inches (100 mm)
Explanation: The NPC requires a minimum 4inch (100 mm) building sewer for singlefamily dwellings. For
commercial or multifamily buildings, the size must be calculated based on fixture unit load.
4. A cleanout is required at a change in direction of the building drain exceeding:
A) 15 degrees
B) 30 degrees
C) 45 degrees
D) 90 degrees
Answer: C) 45 degrees
Explanation: The NPC requires a cleanout at any change in direction of the building drain exceeding 45
degrees. This allows access for clearing blockages.
,5. According to the NPC, what is the MINIMUM trap seal depth required for a plumbing fixture trap?
A) 25 mm (1 inch)
B) 50 mm (2 inches)
C) 75 mm (3 inches)
D) 100 mm (4 inches)
Answer: B) 50 mm (2 inches)
Explanation: NPC Section 2.2.2.1 requires that every trap shall have a water seal of not less than 50 mm
(2 inches) and not more than 100 mm (4 inches). This depth prevents sewer gases from entering the
building while allowing proper drainage.
6. What is the MAXIMUM distance a vent pipe can be from the trap weir of a water closet according to
NPC?
A) 1.5 m (5 ft)
B) 3.0 m (10 ft)
C) 4.5 m (15 ft)
D) 6.0 m (20 ft)
Answer: B) 3.0 m (10 ft)
Explanation: NPC Table 2.2.3.1 specifies maximum distances between trap and vent. For a water closet
(4inch fixture drain), the maximum distance from trap weir to vent is 3.0 m (10 ft). This prevents trap
siphonage and ensures proper drainage.
, 7. The primary purpose of a trap in a drainage system is to:
A) Increase water pressure
B) Prevent sewer gases from entering the building
C) Filter debris
D) Control water temperature
Answer: B) Prevent sewer gases from entering the building
Explanation: A trap holds a small amount of water that blocks sewer gases from entering occupied
spaces.
8. The primary function of a vent pipe is to:
A) Increase water pressure
B) Allow air to enter the drainage system to prevent siphoning
C) Carry sewage to the main line
D) Filter water entering the system
Answer: B) Allow air to enter the drainage system to prevent siphoning
Explanation: Vents maintain proper pressure and allow waste to flow smoothly.
9. What is the minimum slope required for a 3inch horizontal drain line according to the Alberta
Plumbing Code?
A) 1/16 inch per foot
PERIOD) | Latest Update 2026/2027 | 200 Practice Questions and
Verified Answers | Complete Q&A Guide | A+ Graded
SECTION 1: DRAINAGE, WASTE, AND VENT (DWV) SYSTEMS
1. What is the minimum slope for a 4inch (100 mm) horizontal drainage pipe?
A) 1/8 inch per foot (1:96)
B) 1/4 inch per foot (1:48)
C) 1/2 inch per foot (1:24)
D) 3/4 inch per foot (1:16)
Answer: A) 1/8 inch per foot (1:96)
Explanation: The National Plumbing Code of Canada (NPC) requires a minimum slope of 1/8 inch per
foot (or 1:96) for pipes 4 inches (100 mm) and larger. For pipes 3 inches (75 mm) and smaller, the
minimum slope is 1/4 inch per foot (1:48).
2. The maximum number of fixture units allowed on a 4inch (100 mm) building drain with a slope of 1/8
inch per foot is:
A) 180 FU
B) 216 FU
C) 360 FU
D) 500 FU
Answer: B) 216 FU
,Explanation: According to NPC tables, a 4inch (100 mm) building drain at 1/8 inch per foot slope can
carry a maximum of 216 fixture units. At 1/4 inch per foot slope, the capacity increases to 432 fixture
units.
3. The minimum size of a building sewer (service line) for a singlefamily dwelling is:
A) 3 inches (75 mm)
B) 4 inches (100 mm)
C) 6 inches (150 mm)
D) 8 inches (200 mm)
Answer: B) 4 inches (100 mm)
Explanation: The NPC requires a minimum 4inch (100 mm) building sewer for singlefamily dwellings. For
commercial or multifamily buildings, the size must be calculated based on fixture unit load.
4. A cleanout is required at a change in direction of the building drain exceeding:
A) 15 degrees
B) 30 degrees
C) 45 degrees
D) 90 degrees
Answer: C) 45 degrees
Explanation: The NPC requires a cleanout at any change in direction of the building drain exceeding 45
degrees. This allows access for clearing blockages.
,5. According to the NPC, what is the MINIMUM trap seal depth required for a plumbing fixture trap?
A) 25 mm (1 inch)
B) 50 mm (2 inches)
C) 75 mm (3 inches)
D) 100 mm (4 inches)
Answer: B) 50 mm (2 inches)
Explanation: NPC Section 2.2.2.1 requires that every trap shall have a water seal of not less than 50 mm
(2 inches) and not more than 100 mm (4 inches). This depth prevents sewer gases from entering the
building while allowing proper drainage.
6. What is the MAXIMUM distance a vent pipe can be from the trap weir of a water closet according to
NPC?
A) 1.5 m (5 ft)
B) 3.0 m (10 ft)
C) 4.5 m (15 ft)
D) 6.0 m (20 ft)
Answer: B) 3.0 m (10 ft)
Explanation: NPC Table 2.2.3.1 specifies maximum distances between trap and vent. For a water closet
(4inch fixture drain), the maximum distance from trap weir to vent is 3.0 m (10 ft). This prevents trap
siphonage and ensures proper drainage.
, 7. The primary purpose of a trap in a drainage system is to:
A) Increase water pressure
B) Prevent sewer gases from entering the building
C) Filter debris
D) Control water temperature
Answer: B) Prevent sewer gases from entering the building
Explanation: A trap holds a small amount of water that blocks sewer gases from entering occupied
spaces.
8. The primary function of a vent pipe is to:
A) Increase water pressure
B) Allow air to enter the drainage system to prevent siphoning
C) Carry sewage to the main line
D) Filter water entering the system
Answer: B) Allow air to enter the drainage system to prevent siphoning
Explanation: Vents maintain proper pressure and allow waste to flow smoothly.
9. What is the minimum slope required for a 3inch horizontal drain line according to the Alberta
Plumbing Code?
A) 1/16 inch per foot
