Master Plumber Exam Practice Test |
Comprehensive Practice Exam with Verified
Questions, Correct Answers and Detailed
Rationales | Latest Update 2026/2027 –
Already Graded A+
Question 1
Joints between different grades of plastic pipe or between plastic pipe and other
piping material shall be made with an approved:
A. Soldered joint
B. Brazed joint
C. Compression adapter fitting
D. Threaded joint
Answer: C
Rationale: Compression adapter fittings are the approved method for joining
different grades of plastic pipe or connecting plastic pipe to other piping materials.
These fittings provide a secure, leak-proof connection that accommodates the
different expansion and contraction rates of dissimilar materials. Soldered joints
(A) are for copper, brazed joints (B) are for high-temperature applications, and
threaded joints (D) are not suitable for plastic pipes as they can crack the pipe.
Question 2
What is the minimum width specified for passageways leading to an attic water
heater according to the Revised National Plumbing Code of the Philippines?
A. 48 inches wide
B. 36 inches wide
C. 60 inches wide
D. 24 inches wide
Answer: B
Rationale: The Revised National Plumbing Code of the Philippines requires a
minimum passageway width of 36 inches (3 feet) for access to attic water heaters.
This ensures safe access for maintenance, repair, and emergency situations. A 48-
pg. 1
,inch width (A) exceeds requirements, 60 inches (C) is excessive, and 24 inches (D)
is insufficient for safe access.
Question 3
Describe the purpose of an inside storm drain in a plumbing system:
A. An inside storm drain is used to transport sewage away from the building
B. An inside storm drain is a type of venting system for plumbing fixtures
C. An inside storm drain is designed to collect and manage excess rainwater or
stormwater that accumulates within a building, preventing flooding and water
damage
D. An inside storm drain is primarily used for drainage of wastewater from sinks
Answer: C
Rationale: An inside storm drain is specifically designed to collect and manage
excess rainwater or stormwater that accumulates within a building, preventing
flooding and water damage. It is not for sewage (A), venting (B), or sink
wastewater (D). Storm drains handle rainwater and surface runoff, not sanitary
waste.
Question 4
Vent pipes may offset horizontally when the distance above the extreme overflow
level of the fixture is at least:
A. 18" (45.72 cm)
B. 1' (30.48 cm)
C. 6" (15.24 cm)
D. 1" (2.54 cm)
Answer: C
Rationale: Vent pipes may offset horizontally when the distance above the
extreme overflow level of the fixture is at least 6 inches (15.24 cm). This ensures
proper venting and prevents water from backing up into the vent system. The 6-
inch clearance allows for proper drainage while maintaining the vent's function.
Question 5
What is the shape of the cross section used for sizing values of gutters according to
the CODE?
A. Circular
pg. 2
,B. Rectangular
C. Semi-circular
D. Triangular
Answer: B
Rationale: Rectangular is the shape of the cross section used for sizing values of
gutters according to the Plumbing Code. The rectangular shape affects the flow
capacity and efficiency of gutters in plumbing systems. Different shapes have
different hydraulic characteristics that affect how water flows through them.
Question 6
What is the required design specification for a pneumatic tank to ensure adequate
water pressure in a building?
A. Half the total dynamic pressure required
B. Twice the maximum total dynamic pressure required
C. Three times the maximum total dynamic pressure required
D. Equal to the maximum static pressure needed
Answer: B
Rationale: A pneumatic tank must be designed to provide twice the maximum
total dynamic pressure required to ensure adequate water pressure in all floors of a
building. This ensures consistent water pressure across all floors and compensates
for pressure losses in the system. Designing to twice the maximum pressure
provides a safety margin and prevents pressure fluctuations.
Question 7
What is the minimum required diameter for the waste and overflow pipe of a
bathtub according to plumbing standards?
A. 2" OD
B. 1-1/2" OD
C. 1-1/4" OD
D. 1" OD
Answer: B
Rationale: The minimum required diameter for the waste and overflow pipe of a
bathtub is 1-1/2 inches OD. This size ensures adequate drainage capacity for
bathtubs, which typically discharge water at a rapid rate. A 2-inch pipe (A) is
larger than required, while 1-1/4 inch (C) and 1 inch (D) are insufficient for proper
pg. 3
, drainage.
Question 8
What is the minimum size of water supply inlet for a lavatory (circular or
multiple)?
A. 1 in
B. 1/2 in
C. 3/8 in
D. 3/4 in
Answer: B
Rationale: The minimum size of water supply inlet for a lavatory is 1/2 inch. This
ensures adequate water flow and pressure for lavatories. A 1-inch inlet (A) is too
large for a lavatory, 3/8 inch (C) is insufficient, and 3/4 inch (D) is typically used
for larger fixtures.
Question 9
Support hangers for 10-foot lengths of cast iron soil pipe suspended from a ceiling
shall be spaced not more than ______ feet:
A. 2.5
B. 5
C. 10
D. 7.5
Answer: B
Rationale: Support hangers for 10-foot lengths of cast iron soil pipe suspended
from a ceiling shall be spaced not more than 5 feet apart. This spacing ensures
proper support for the heavy cast iron pipe, preventing sagging and potential
damage. The 5-foot spacing is required to distribute the weight of the pipe
adequately.
Question 10
If a plumbing installation does not adhere to the guidelines set forth in Section
201.6, what potential issue could arise during a plumbing inspection?
A. Inadequate water supply pressure
B. Excessive noise from plumbing fixtures
C. Failure to meet aesthetic standards
pg. 4
Comprehensive Practice Exam with Verified
Questions, Correct Answers and Detailed
Rationales | Latest Update 2026/2027 –
Already Graded A+
Question 1
Joints between different grades of plastic pipe or between plastic pipe and other
piping material shall be made with an approved:
A. Soldered joint
B. Brazed joint
C. Compression adapter fitting
D. Threaded joint
Answer: C
Rationale: Compression adapter fittings are the approved method for joining
different grades of plastic pipe or connecting plastic pipe to other piping materials.
These fittings provide a secure, leak-proof connection that accommodates the
different expansion and contraction rates of dissimilar materials. Soldered joints
(A) are for copper, brazed joints (B) are for high-temperature applications, and
threaded joints (D) are not suitable for plastic pipes as they can crack the pipe.
Question 2
What is the minimum width specified for passageways leading to an attic water
heater according to the Revised National Plumbing Code of the Philippines?
A. 48 inches wide
B. 36 inches wide
C. 60 inches wide
D. 24 inches wide
Answer: B
Rationale: The Revised National Plumbing Code of the Philippines requires a
minimum passageway width of 36 inches (3 feet) for access to attic water heaters.
This ensures safe access for maintenance, repair, and emergency situations. A 48-
pg. 1
,inch width (A) exceeds requirements, 60 inches (C) is excessive, and 24 inches (D)
is insufficient for safe access.
Question 3
Describe the purpose of an inside storm drain in a plumbing system:
A. An inside storm drain is used to transport sewage away from the building
B. An inside storm drain is a type of venting system for plumbing fixtures
C. An inside storm drain is designed to collect and manage excess rainwater or
stormwater that accumulates within a building, preventing flooding and water
damage
D. An inside storm drain is primarily used for drainage of wastewater from sinks
Answer: C
Rationale: An inside storm drain is specifically designed to collect and manage
excess rainwater or stormwater that accumulates within a building, preventing
flooding and water damage. It is not for sewage (A), venting (B), or sink
wastewater (D). Storm drains handle rainwater and surface runoff, not sanitary
waste.
Question 4
Vent pipes may offset horizontally when the distance above the extreme overflow
level of the fixture is at least:
A. 18" (45.72 cm)
B. 1' (30.48 cm)
C. 6" (15.24 cm)
D. 1" (2.54 cm)
Answer: C
Rationale: Vent pipes may offset horizontally when the distance above the
extreme overflow level of the fixture is at least 6 inches (15.24 cm). This ensures
proper venting and prevents water from backing up into the vent system. The 6-
inch clearance allows for proper drainage while maintaining the vent's function.
Question 5
What is the shape of the cross section used for sizing values of gutters according to
the CODE?
A. Circular
pg. 2
,B. Rectangular
C. Semi-circular
D. Triangular
Answer: B
Rationale: Rectangular is the shape of the cross section used for sizing values of
gutters according to the Plumbing Code. The rectangular shape affects the flow
capacity and efficiency of gutters in plumbing systems. Different shapes have
different hydraulic characteristics that affect how water flows through them.
Question 6
What is the required design specification for a pneumatic tank to ensure adequate
water pressure in a building?
A. Half the total dynamic pressure required
B. Twice the maximum total dynamic pressure required
C. Three times the maximum total dynamic pressure required
D. Equal to the maximum static pressure needed
Answer: B
Rationale: A pneumatic tank must be designed to provide twice the maximum
total dynamic pressure required to ensure adequate water pressure in all floors of a
building. This ensures consistent water pressure across all floors and compensates
for pressure losses in the system. Designing to twice the maximum pressure
provides a safety margin and prevents pressure fluctuations.
Question 7
What is the minimum required diameter for the waste and overflow pipe of a
bathtub according to plumbing standards?
A. 2" OD
B. 1-1/2" OD
C. 1-1/4" OD
D. 1" OD
Answer: B
Rationale: The minimum required diameter for the waste and overflow pipe of a
bathtub is 1-1/2 inches OD. This size ensures adequate drainage capacity for
bathtubs, which typically discharge water at a rapid rate. A 2-inch pipe (A) is
larger than required, while 1-1/4 inch (C) and 1 inch (D) are insufficient for proper
pg. 3
, drainage.
Question 8
What is the minimum size of water supply inlet for a lavatory (circular or
multiple)?
A. 1 in
B. 1/2 in
C. 3/8 in
D. 3/4 in
Answer: B
Rationale: The minimum size of water supply inlet for a lavatory is 1/2 inch. This
ensures adequate water flow and pressure for lavatories. A 1-inch inlet (A) is too
large for a lavatory, 3/8 inch (C) is insufficient, and 3/4 inch (D) is typically used
for larger fixtures.
Question 9
Support hangers for 10-foot lengths of cast iron soil pipe suspended from a ceiling
shall be spaced not more than ______ feet:
A. 2.5
B. 5
C. 10
D. 7.5
Answer: B
Rationale: Support hangers for 10-foot lengths of cast iron soil pipe suspended
from a ceiling shall be spaced not more than 5 feet apart. This spacing ensures
proper support for the heavy cast iron pipe, preventing sagging and potential
damage. The 5-foot spacing is required to distribute the weight of the pipe
adequately.
Question 10
If a plumbing installation does not adhere to the guidelines set forth in Section
201.6, what potential issue could arise during a plumbing inspection?
A. Inadequate water supply pressure
B. Excessive noise from plumbing fixtures
C. Failure to meet aesthetic standards
pg. 4
