Kansas Master Plumber / Journeyman
Plumber Examination Practice Questions
And Correct Ans
1. In a 12-story building, a horizontal wet vent connects a lavatory and a water closet
on the same floor. The lavatory drain is 1-1/2 inches and the water closet drain is 3
inches. If the wet vent is sized as a dry vent for the water closet, what is the minimum
required diameter of the wet vent section per IPC?
A. 1-1/2 inches
B. 2 inches
C. 3 inches
D. 4 inches
Answer: B. 2 inches
Rationale: IPC Table 912.3 requires a wet vent to be at least 2 inches for a water closet,
but not less than the required dry vent size. The lavatory drain is 1-1/2 inches, so the wet
vent must be increased to 2 inches to serve as a wet vent for the WC. Options A, C, and D
are incorrect because 1-1/2 inches is too small for a WC wet vent, and 3 or 4 inches exceed
the minimum.
2. A backflow prevention assembly is required on a fire sprinkler system connected to
a municipal water supply. The system uses antifreeze (glycerin) and is a wet pipe
system. Which type of assembly is most appropriate and code-compliant?
A. Double check valve assembly (DCVA)
B. Reduced pressure principle assembly (RPZ)
C. Pressure vacuum breaker (PVB)
D. Atmospheric vacuum breaker (AVB)
Answer: B. Reduced pressure principle assembly (RPZ)
Rationale: An RPZ is required for systems containing antifreeze because it provides
protection against both backsiphonage and backpressure, and it is the only assembly listed
for high-hazard cross-connections. DCVA is for low hazard, PVB and AVB cannot be used
under continuous pressure or for antifreeze solutions.
Page 1 of 77
,3. Using the parallel piping method, two 1-inch copper tubes of equal length supply a
fixture. If the total flow required is 20 gpm, what is the flow rate in each tube
assuming equal resistance?
A. 5 gpm
B. 10 gpm
C. 15 gpm
D. 20 gpm
Answer: B. 10 gpm
Rationale: In parallel piping with equal length and diameter, flow splits equally, so each
tube carries half the total flow: 20 gpm / 2 = 10 gpm. Options A, C, and D do not reflect
equal distribution.
4. A 4-inch building drain slopes at 1/8 inch per foot. What is the maximum allowable
length of a 4-inch horizontal fixture branch before a cleanout is required per IPC?
A. 50 feet
B. 75 feet
C. 100 feet
D. 125 feet
Answer: C. 100 feet
Rationale: IPC Section 708.1 requires a cleanout at the end of each horizontal drain and at
intervals not exceeding 100 feet for 4-inch and larger pipes. Thus, the maximum length is
100 feet. Options A, B, and D are incorrect because they do not match the code maximum.
Page 2 of 77
,5. A gas water heater is installed in a garage. The ignition source is 18 inches above the
floor. Per IFGC, what is the minimum required elevation of the ignition source above
the floor in a garage?
A. 12 inches
B. 18 inches
C. 24 inches
D. 36 inches
Answer: B. 18 inches
Rationale: IFGC Section 305.3 requires ignition sources in garages to be at least 18 inches
above the floor to avoid flammable vapors. Options A, C, and D are incorrect because they
do not match the code minimum.
6. A solar thermal system preheats water for a commercial kitchen. The system uses a
closed-loop glycol mixture. Which backflow prevention method is required at the
potable water make-up connection?
A. Air gap
B. RPZ
C. DCVA
D. PVB
Answer: A. Air gap
Rationale: An air gap provides the highest level of protection against cross-connection and
is required for make-up water to a non-potable closed-loop system. RPZ, DCVA, and PVB
are mechanical assemblies that are acceptable but not as reliable as an air gap for this
high-hazard application.
Page 3 of 77
, 7. A 2-inch PVC DWV pipe passes through a 2x4 wood stud wall. What is the
minimum required protection from nail penetration per IPC?
A. Steel nail plate at least 1/16 inch thick
B. Steel nail plate at least 1/8 inch thick
C. Plastic shield at least 1/8 inch thick
D. No protection required if pipe is centered
Answer: A. Steel nail plate at least 1/16 inch thick
Rationale: IPC Section 305.6 requires a steel nail plate at least 1/16 inch thick to protect
pipe from nail penetration. Options B and C specify incorrect thickness or material, and D
is incorrect because protection is always required when pipe is within 1-1/2 inches of the
stud edge.
8. A water heater is installed in a seismic zone. Per IPC, which of the following is
required for strapping?
A. One strap in the upper third
B. Two straps, one in upper third and one in lower third
C. Two straps, both in upper half
D. Three straps evenly spaced
Answer: B. Two straps, one in upper third and one in lower third
Rationale: IPC Section 507.2 requires two straps for seismic zones: one in the upper third
and one in the lower third of the tank. Options A, C, and D do not meet the code
requirement.
Page 4 of 77
Plumber Examination Practice Questions
And Correct Ans
1. In a 12-story building, a horizontal wet vent connects a lavatory and a water closet
on the same floor. The lavatory drain is 1-1/2 inches and the water closet drain is 3
inches. If the wet vent is sized as a dry vent for the water closet, what is the minimum
required diameter of the wet vent section per IPC?
A. 1-1/2 inches
B. 2 inches
C. 3 inches
D. 4 inches
Answer: B. 2 inches
Rationale: IPC Table 912.3 requires a wet vent to be at least 2 inches for a water closet,
but not less than the required dry vent size. The lavatory drain is 1-1/2 inches, so the wet
vent must be increased to 2 inches to serve as a wet vent for the WC. Options A, C, and D
are incorrect because 1-1/2 inches is too small for a WC wet vent, and 3 or 4 inches exceed
the minimum.
2. A backflow prevention assembly is required on a fire sprinkler system connected to
a municipal water supply. The system uses antifreeze (glycerin) and is a wet pipe
system. Which type of assembly is most appropriate and code-compliant?
A. Double check valve assembly (DCVA)
B. Reduced pressure principle assembly (RPZ)
C. Pressure vacuum breaker (PVB)
D. Atmospheric vacuum breaker (AVB)
Answer: B. Reduced pressure principle assembly (RPZ)
Rationale: An RPZ is required for systems containing antifreeze because it provides
protection against both backsiphonage and backpressure, and it is the only assembly listed
for high-hazard cross-connections. DCVA is for low hazard, PVB and AVB cannot be used
under continuous pressure or for antifreeze solutions.
Page 1 of 77
,3. Using the parallel piping method, two 1-inch copper tubes of equal length supply a
fixture. If the total flow required is 20 gpm, what is the flow rate in each tube
assuming equal resistance?
A. 5 gpm
B. 10 gpm
C. 15 gpm
D. 20 gpm
Answer: B. 10 gpm
Rationale: In parallel piping with equal length and diameter, flow splits equally, so each
tube carries half the total flow: 20 gpm / 2 = 10 gpm. Options A, C, and D do not reflect
equal distribution.
4. A 4-inch building drain slopes at 1/8 inch per foot. What is the maximum allowable
length of a 4-inch horizontal fixture branch before a cleanout is required per IPC?
A. 50 feet
B. 75 feet
C. 100 feet
D. 125 feet
Answer: C. 100 feet
Rationale: IPC Section 708.1 requires a cleanout at the end of each horizontal drain and at
intervals not exceeding 100 feet for 4-inch and larger pipes. Thus, the maximum length is
100 feet. Options A, B, and D are incorrect because they do not match the code maximum.
Page 2 of 77
,5. A gas water heater is installed in a garage. The ignition source is 18 inches above the
floor. Per IFGC, what is the minimum required elevation of the ignition source above
the floor in a garage?
A. 12 inches
B. 18 inches
C. 24 inches
D. 36 inches
Answer: B. 18 inches
Rationale: IFGC Section 305.3 requires ignition sources in garages to be at least 18 inches
above the floor to avoid flammable vapors. Options A, C, and D are incorrect because they
do not match the code minimum.
6. A solar thermal system preheats water for a commercial kitchen. The system uses a
closed-loop glycol mixture. Which backflow prevention method is required at the
potable water make-up connection?
A. Air gap
B. RPZ
C. DCVA
D. PVB
Answer: A. Air gap
Rationale: An air gap provides the highest level of protection against cross-connection and
is required for make-up water to a non-potable closed-loop system. RPZ, DCVA, and PVB
are mechanical assemblies that are acceptable but not as reliable as an air gap for this
high-hazard application.
Page 3 of 77
, 7. A 2-inch PVC DWV pipe passes through a 2x4 wood stud wall. What is the
minimum required protection from nail penetration per IPC?
A. Steel nail plate at least 1/16 inch thick
B. Steel nail plate at least 1/8 inch thick
C. Plastic shield at least 1/8 inch thick
D. No protection required if pipe is centered
Answer: A. Steel nail plate at least 1/16 inch thick
Rationale: IPC Section 305.6 requires a steel nail plate at least 1/16 inch thick to protect
pipe from nail penetration. Options B and C specify incorrect thickness or material, and D
is incorrect because protection is always required when pipe is within 1-1/2 inches of the
stud edge.
8. A water heater is installed in a seismic zone. Per IPC, which of the following is
required for strapping?
A. One strap in the upper third
B. Two straps, one in upper third and one in lower third
C. Two straps, both in upper half
D. Three straps evenly spaced
Answer: B. Two straps, one in upper third and one in lower third
Rationale: IPC Section 507.2 requires two straps for seismic zones: one in the upper third
and one in the lower third of the tank. Options A, C, and D do not meet the code
requirement.
Page 4 of 77
