249 Pennsylvania Master Plumber Practice
Exam Questions and Correct Answers
(Verified Answers) Plus Rationale 2027 Q&A|
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1. A drainage pipe that is not sized to carry the discharge of a sump pump is
considered a violation. What is the minimum required size for a building drain that
receives discharge from a sump pump under the Philadelphia Plumbing Code?
• A) 1½ inches
• B) 2 inches
• C) 3 inches
• D) 4 inches
Answer: C – 3 inches
Rationale: While the 2021 IPC base says 2 inches, Philadelphia Code amendments often
require a 3-inch minimum building drain when a sump pump discharges into it to prevent
surcharging .
2. According to the Philadelphia Master Plumber exam standards, what is the
maximum distance a trap can be from a vent for a 2-inch fixture drain under the
IPC?
• A) 4 feet
• B) 5 feet
• C) 6 feet
• D) 8 feet
Answer: D – 8 feet
,Rationale: IPC Table 909.1 allows a 2-inch trap-to-vent distance of 8 feet (at ¼ inch per
foot slope). Philadelphia adopts this without change for residential applications .
3. A backflow prevention device is required on a residential water service if a
chemical injection system is present. Which device is minimally acceptable for a
low-hazard application?
• A) Double check valve assembly (DCVA)
• B) Reduced pressure zone (RPZ)
• C) Atmospheric vacuum breaker (AVB)
• D) Pressure vacuum breaker (PVB)
Answer: A – Double check valve assembly (DCVA)
Rationale: For a low hazard (e.g., fertilizer injector), a DCVA is the minimum acceptable
device. An RPZ is required for high-hazard applications .
4. The Philadelphia Code mandates that a sump pump discharge line must
discharge to which location?
• A) The sanitary sewer
• B) The storm sewer or outside grade
• C) The building drain before the main trap
• D) Any floor drain
Answer: B – The storm sewer or outside grade
Rationale: Sump pumps handling groundwater or stormwater cannot discharge to sanitary
sewers in Philadelphia due to combined sewer overflow (CSO) regulations .
5. What is the minimum size of a plumbing vent passing through a roof in
Philadelphia for a 3-inch waste stack?
, • A) 1¼ inches
• B) 1½ inches
• C) 3 inches
• D) 2 inches
Answer: C – 3 inches
Rationale: The vent must be at least half the diameter of the drain it serves, but
Philadelphia requires the vent through the roof to be 3 inches to prevent ice closure .
6. Which fitting is prohibited for use as a drainage pattern change from horizontal
to vertical?
• A) Long sweep 90°
• B) Medium sweep 90°
• C) Sanitary tee on its back
• D) Wye and 45°
Answer: C – Sanitary tee on its back
Rationale: A sanitary tee on its back is not allowed for horizontal to vertical drainage flow
because it causes a directional change without a sweep. It is only allowed for vent
connections .
7. A backwater valve is required on every building drain where the lowest possible
fixture is below the next upstream manhole cover elevation. What type of valve is
approved in Philadelphia?
• A) Gate valve
• B) Ball valve
• C) Swing check type backwater valve
• D) Full port plug valve
, Answer: C – Swing check type backwater valve
Rationale: Swing check type backwater valves with access covers are required by the
Philadelphia Plumbing Code (PPM Chapter 8) for flood protection .
8. What is the maximum horizontal length of a fixture drain for a water closet with
a 3-inch trap arm vented within permitted distance?
• A) 6 feet
• B) 8 feet
• C) 10 feet
• D) 12 feet
Answer: D – 12 feet
Rationale: IPC Table 909.1 allows a 3-inch trap arm (trap to vent) length of 12 feet at ¼-
inch per foot slope .
9. In Philadelphia, water service pipe from the main to the building must be buried
at least how deep below grade to prevent freezing?
• A) 24 inches
• B) 30 inches
• C) 36 inches
• D) 42 inches
Answer: C – 36 inches
Rationale: Philadelphia's frost depth is approximately 30 inches, but the code requires 36
inches (3 feet) for water service below ground to ensure safety .
10. What is the minimum grade for a 4-inch building sewer under the IPC and
Philadelphia amendments?
Exam Questions and Correct Answers
(Verified Answers) Plus Rationale 2027 Q&A|
Instant Download Pdf
1. A drainage pipe that is not sized to carry the discharge of a sump pump is
considered a violation. What is the minimum required size for a building drain that
receives discharge from a sump pump under the Philadelphia Plumbing Code?
• A) 1½ inches
• B) 2 inches
• C) 3 inches
• D) 4 inches
Answer: C – 3 inches
Rationale: While the 2021 IPC base says 2 inches, Philadelphia Code amendments often
require a 3-inch minimum building drain when a sump pump discharges into it to prevent
surcharging .
2. According to the Philadelphia Master Plumber exam standards, what is the
maximum distance a trap can be from a vent for a 2-inch fixture drain under the
IPC?
• A) 4 feet
• B) 5 feet
• C) 6 feet
• D) 8 feet
Answer: D – 8 feet
,Rationale: IPC Table 909.1 allows a 2-inch trap-to-vent distance of 8 feet (at ¼ inch per
foot slope). Philadelphia adopts this without change for residential applications .
3. A backflow prevention device is required on a residential water service if a
chemical injection system is present. Which device is minimally acceptable for a
low-hazard application?
• A) Double check valve assembly (DCVA)
• B) Reduced pressure zone (RPZ)
• C) Atmospheric vacuum breaker (AVB)
• D) Pressure vacuum breaker (PVB)
Answer: A – Double check valve assembly (DCVA)
Rationale: For a low hazard (e.g., fertilizer injector), a DCVA is the minimum acceptable
device. An RPZ is required for high-hazard applications .
4. The Philadelphia Code mandates that a sump pump discharge line must
discharge to which location?
• A) The sanitary sewer
• B) The storm sewer or outside grade
• C) The building drain before the main trap
• D) Any floor drain
Answer: B – The storm sewer or outside grade
Rationale: Sump pumps handling groundwater or stormwater cannot discharge to sanitary
sewers in Philadelphia due to combined sewer overflow (CSO) regulations .
5. What is the minimum size of a plumbing vent passing through a roof in
Philadelphia for a 3-inch waste stack?
, • A) 1¼ inches
• B) 1½ inches
• C) 3 inches
• D) 2 inches
Answer: C – 3 inches
Rationale: The vent must be at least half the diameter of the drain it serves, but
Philadelphia requires the vent through the roof to be 3 inches to prevent ice closure .
6. Which fitting is prohibited for use as a drainage pattern change from horizontal
to vertical?
• A) Long sweep 90°
• B) Medium sweep 90°
• C) Sanitary tee on its back
• D) Wye and 45°
Answer: C – Sanitary tee on its back
Rationale: A sanitary tee on its back is not allowed for horizontal to vertical drainage flow
because it causes a directional change without a sweep. It is only allowed for vent
connections .
7. A backwater valve is required on every building drain where the lowest possible
fixture is below the next upstream manhole cover elevation. What type of valve is
approved in Philadelphia?
• A) Gate valve
• B) Ball valve
• C) Swing check type backwater valve
• D) Full port plug valve
, Answer: C – Swing check type backwater valve
Rationale: Swing check type backwater valves with access covers are required by the
Philadelphia Plumbing Code (PPM Chapter 8) for flood protection .
8. What is the maximum horizontal length of a fixture drain for a water closet with
a 3-inch trap arm vented within permitted distance?
• A) 6 feet
• B) 8 feet
• C) 10 feet
• D) 12 feet
Answer: D – 12 feet
Rationale: IPC Table 909.1 allows a 3-inch trap arm (trap to vent) length of 12 feet at ¼-
inch per foot slope .
9. In Philadelphia, water service pipe from the main to the building must be buried
at least how deep below grade to prevent freezing?
• A) 24 inches
• B) 30 inches
• C) 36 inches
• D) 42 inches
Answer: C – 36 inches
Rationale: Philadelphia's frost depth is approximately 30 inches, but the code requires 36
inches (3 feet) for water service below ground to ensure safety .
10. What is the minimum grade for a 4-inch building sewer under the IPC and
Philadelphia amendments?
