Master Plumber Exam Prep: 150 Core Questions &
Answers
(Based on IPC & UPC – Journeyman & Master
Licensing Levels)
Introduction
Passing your plumbing licensing examination requires more than just on-the-job
experience – you need a deep, code-based understanding of fixture requirements,
drainage and venting (DWV), water supply sizing, gas piping, backflow prevention,
safety protocols, and trade math. This practice exam is designed to mirror the difficulty,
structure, and content of real state plumbing board exams (including PSI, Pearson
VUE, and Prov exams).
BATCH 1: Questions 1–50
(Code Essentials, Fixtures, Traps, Backflow, Water Heaters)
1. What is the minimum distance from a bathtub rim to the control valve?
A) 1 inch
B) 2 inches
C) 4 inches
D) 6 inches
2. A “combination fixture” (e.g., laundry tub) requires a trap size of at least:
A) 1 1/4 inch
B) 1 1/2 inch
C) 2 inches
D) 2 1/2 inches
3. What is the maximum allowable temperature for a residential hand-held shower
hose?
,A) 100°F
B) 120°F
C) 140°F
D) 160°F
4. The minimum water supply pipe size for a dishwasher is:
A) 1/4 inch
B) 3/8 inch
C) 1/2 inch
D) 3/4 inch
5. A “bubbler” drinking fountain must have a waste line of at least:
A) 1 inch
B) 1 1/4 inch
C) 1 1/2 inch
D) 2 inches
6. What is the maximum distance from a floor drain to a trap primer?
A) 2 ft
B) 5 ft
C) 10 ft
D) 15 ft
7. How often should a trap primer discharge (typical code)?
A) Every hour
B) When a nearby fixture is used
C) Once per day
D) Continuously
8. The minimum size for a residential sump pump discharge line (outside) is:
A) 1 inch
B) 1 1/4 inch
C) 1 1/2 inch
D) 2 inches
9. A “check valve” on a sump pump discharge must be located:
A) At the pump outlet
B) Within 6 inches of the pump
C) At the building wall
D) Above grade
, 10. What is the maximum head pressure for a typical 1/2 HP sump pump?
A) 5 ft
B) 10 ft
C) 20 ft
D) 30 ft
11. The minimum distance between the water heater relief valve discharge and the floor
drain is:
A) 1 inch
B) 6 inches (air gap)
C) 12 inches
D) 24 inches
12. A “direct vent” water heater draws combustion air from:
A) Inside the room
B) Outside through a concentric pipe
C) The attic
D) The crawlspace
13. What is the minimum clearance from a water heater vent to a window?
A) 1 ft
B) 4 ft (horizontal)
C) 6 ft
D) 10 ft
14. The maximum water heater tank temperature setting for a daycare facility is:
A) 100°F
B) 110°F
C) 120°F
D) 130°F
15. A “tankless” water heater has a minimum flow rate to activate:
A) 0.2 gpm
B) 0.5 gpm
C) 1.0 gpm
D) 1.5 gpm
16. What is the minimum gas line size for a tankless water heater rated at 199,000
BTU/hr at 20 ft?
A) 1/2 inch
B) 3/4 inch
Answers
(Based on IPC & UPC – Journeyman & Master
Licensing Levels)
Introduction
Passing your plumbing licensing examination requires more than just on-the-job
experience – you need a deep, code-based understanding of fixture requirements,
drainage and venting (DWV), water supply sizing, gas piping, backflow prevention,
safety protocols, and trade math. This practice exam is designed to mirror the difficulty,
structure, and content of real state plumbing board exams (including PSI, Pearson
VUE, and Prov exams).
BATCH 1: Questions 1–50
(Code Essentials, Fixtures, Traps, Backflow, Water Heaters)
1. What is the minimum distance from a bathtub rim to the control valve?
A) 1 inch
B) 2 inches
C) 4 inches
D) 6 inches
2. A “combination fixture” (e.g., laundry tub) requires a trap size of at least:
A) 1 1/4 inch
B) 1 1/2 inch
C) 2 inches
D) 2 1/2 inches
3. What is the maximum allowable temperature for a residential hand-held shower
hose?
,A) 100°F
B) 120°F
C) 140°F
D) 160°F
4. The minimum water supply pipe size for a dishwasher is:
A) 1/4 inch
B) 3/8 inch
C) 1/2 inch
D) 3/4 inch
5. A “bubbler” drinking fountain must have a waste line of at least:
A) 1 inch
B) 1 1/4 inch
C) 1 1/2 inch
D) 2 inches
6. What is the maximum distance from a floor drain to a trap primer?
A) 2 ft
B) 5 ft
C) 10 ft
D) 15 ft
7. How often should a trap primer discharge (typical code)?
A) Every hour
B) When a nearby fixture is used
C) Once per day
D) Continuously
8. The minimum size for a residential sump pump discharge line (outside) is:
A) 1 inch
B) 1 1/4 inch
C) 1 1/2 inch
D) 2 inches
9. A “check valve” on a sump pump discharge must be located:
A) At the pump outlet
B) Within 6 inches of the pump
C) At the building wall
D) Above grade
, 10. What is the maximum head pressure for a typical 1/2 HP sump pump?
A) 5 ft
B) 10 ft
C) 20 ft
D) 30 ft
11. The minimum distance between the water heater relief valve discharge and the floor
drain is:
A) 1 inch
B) 6 inches (air gap)
C) 12 inches
D) 24 inches
12. A “direct vent” water heater draws combustion air from:
A) Inside the room
B) Outside through a concentric pipe
C) The attic
D) The crawlspace
13. What is the minimum clearance from a water heater vent to a window?
A) 1 ft
B) 4 ft (horizontal)
C) 6 ft
D) 10 ft
14. The maximum water heater tank temperature setting for a daycare facility is:
A) 100°F
B) 110°F
C) 120°F
D) 130°F
15. A “tankless” water heater has a minimum flow rate to activate:
A) 0.2 gpm
B) 0.5 gpm
C) 1.0 gpm
D) 1.5 gpm
16. What is the minimum gas line size for a tankless water heater rated at 199,000
BTU/hr at 20 ft?
A) 1/2 inch
B) 3/4 inch
