MASTER PLUMBING WSSC EXAM
QUESTIONS AND ANSWERS 2026
VERIFIED.
Who is responsible for maintaining the plumbing system in a safe condition? - ANS The
owner or owner's agent is responsible.
Before work commences when must a permit be obtained? - ANS A permit must be obtained
or a 100% (Double the normal fee) will be charged.
Underground Piping - ANS All underground piping shall be left uncovered until inspected.
Inspector's Authority - ANS The inspector has authority to stop work being done dangerously
or unsafely.
Air Gap - ANS The vertical distance between the opening of the water supply and flood level
rim of a receptacle.
Branch - ANS Any part of the piping system except mains, stacks or risers.
Branch Vent - ANS A vent connecting individual vents with a stack vent or vent stack.
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,Building Drain - ANS The lowest part of a drainage system which receives waste from soil and
waste pipes and connects to the building sewer.
Building Sewer - ANS Drainage piping that conveys waste from the building drain to the
public sewer or disposal system.
Cleanout - ANS Access opening in the drainage system used to remove obstructions.
Combination Fixture - ANS Two or three compartment sink drained by a continuous waste
connected to one trap.
Combinate Waste and Vent System - ANS Horizontal wet venting system for sinks and floor
drains.
Common Vent - ANS A single vent serving as the vent for two fixture drains.
Critical Level - ANS Is an elevation mark on a vacuum breaker setting the minimum elevation
device can be installed above the flood level rim of a fixture.
Cross Connection - ANS Is an actual or potential tie between potable water and any source of
pollution or contamination.
Developed Length - ANS A measurement of piping taken along the centerline of pipe and
fittings
Drain - ANS any pipe that conveys waste water in the drainage system.
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, Indirect Waste - ANS Waste pipe that drains through an air gap to the drainage system.
Individual Vent - ANS A pipe installed to vent a fixture trap. It may connect to the vent system
above the fixture or terminate in the open air.
Main - ANS Is the primary or principal pipe that drains through an air gap to the drainage
system.
Potable Water - ANS Is water that is sufficiently free of impurities to meet public health
standards.
Rough In - ANS Parts of the plumbing system that are installed
prior to the installation of fixtures.
Soil Pipe - ANS Is drain pipe conveying sewage containing fecal matter.
Stack Vent - ANS Is the extension of a soil or waste stack above the highest fixture served.
Trap - ANS Is a device that provides a water seal to prevent the passage of sewer gas and
allow the passage of waste.
Trap Seal - ANS Distance from weir to top of the dip of the trap
Vacuum Breaker - ANS Is a backflow preventer that allows air to a vacuum being pulled on a
system.
Vent Stack - ANS A vertical vent pipe to provide circulation of air to and from drainage system
@COPYRIGHT ALL RIGHTS RESERVED PAGE 3 OF 17
QUESTIONS AND ANSWERS 2026
VERIFIED.
Who is responsible for maintaining the plumbing system in a safe condition? - ANS The
owner or owner's agent is responsible.
Before work commences when must a permit be obtained? - ANS A permit must be obtained
or a 100% (Double the normal fee) will be charged.
Underground Piping - ANS All underground piping shall be left uncovered until inspected.
Inspector's Authority - ANS The inspector has authority to stop work being done dangerously
or unsafely.
Air Gap - ANS The vertical distance between the opening of the water supply and flood level
rim of a receptacle.
Branch - ANS Any part of the piping system except mains, stacks or risers.
Branch Vent - ANS A vent connecting individual vents with a stack vent or vent stack.
@COPYRIGHT ALL RIGHTS RESERVED PAGE 1 OF 17
,Building Drain - ANS The lowest part of a drainage system which receives waste from soil and
waste pipes and connects to the building sewer.
Building Sewer - ANS Drainage piping that conveys waste from the building drain to the
public sewer or disposal system.
Cleanout - ANS Access opening in the drainage system used to remove obstructions.
Combination Fixture - ANS Two or three compartment sink drained by a continuous waste
connected to one trap.
Combinate Waste and Vent System - ANS Horizontal wet venting system for sinks and floor
drains.
Common Vent - ANS A single vent serving as the vent for two fixture drains.
Critical Level - ANS Is an elevation mark on a vacuum breaker setting the minimum elevation
device can be installed above the flood level rim of a fixture.
Cross Connection - ANS Is an actual or potential tie between potable water and any source of
pollution or contamination.
Developed Length - ANS A measurement of piping taken along the centerline of pipe and
fittings
Drain - ANS any pipe that conveys waste water in the drainage system.
@COPYRIGHT ALL RIGHTS RESERVED PAGE 2 OF 17
, Indirect Waste - ANS Waste pipe that drains through an air gap to the drainage system.
Individual Vent - ANS A pipe installed to vent a fixture trap. It may connect to the vent system
above the fixture or terminate in the open air.
Main - ANS Is the primary or principal pipe that drains through an air gap to the drainage
system.
Potable Water - ANS Is water that is sufficiently free of impurities to meet public health
standards.
Rough In - ANS Parts of the plumbing system that are installed
prior to the installation of fixtures.
Soil Pipe - ANS Is drain pipe conveying sewage containing fecal matter.
Stack Vent - ANS Is the extension of a soil or waste stack above the highest fixture served.
Trap - ANS Is a device that provides a water seal to prevent the passage of sewer gas and
allow the passage of waste.
Trap Seal - ANS Distance from weir to top of the dip of the trap
Vacuum Breaker - ANS Is a backflow preventer that allows air to a vacuum being pulled on a
system.
Vent Stack - ANS A vertical vent pipe to provide circulation of air to and from drainage system
@COPYRIGHT ALL RIGHTS RESERVED PAGE 3 OF 17
