,National Home Inspector Exam – EXAM STUDY
GUIDE 2026/2027 COMPLETE QUESTIONS
WITH VERIFIED CORRECT ANSWERS || 100%
GUARANTEED PASS
Hydronic heating - ANSWER a heating system that circulates hot liquid or steam through
pipes; the pipes may be installed in the floor, ceiling, or wall, or may serve radiators or similar
devices.
Manifold (vent connector) - ANSWER a type of vent connector in which two or more vent
connectors are joined together before being connected to the vent.
Vent (combustion) - ANSWER the final vertical component in a vent system; this term most
accurately describes manufactured products such as metal pipes.
Vent (connector) - ANSWER a component that conducts combustion products from a fuel-
burning appliance to a vent; vent connectors are single-wall or double-wall metal pipes.
Vent system - ANSWER a passageway that conducts combustion products from a fuel-
burning appliance to a point outside the house; thevent system begins at the appliance draft
hood or flue collar and ends outside the house; the vent system consists of a vent or Chimney
and a vent connector, if one is used.
1/2 Bathroom (half bath) - ANSWER a bathroom with a sink and a toilet; also called a
powder room.
,3/4 Bathroom - ANSWER a bathroom with a sink, toilet, and a shower, but no bathtub
Aerator - ANSWER a device that introduces air into a water stream, usually attached to the
outlet of sink and lavatory faucets.
Adapter - ANSWER a fitting that allows connection of different pipe types or different pipe
sizes.
Air Admittance Valve (AAV) - ANSWER an air pressure operated one-way valve used in place
of an atmospheric plumbing vent; this device is different from a check (cheater) vent which
contains a spring loaded gasket and is not approved for use in site-built houses in most
jurisdictions.
Air gap - ANSWER the vertical distance between the discharge opening of a water supply
fixture, such as a faucet, and the flood rim level of a fixture such as a sink; an air gap is one
method of preventing a cross connection between the water supply and drainage supply.
Appliance, plumbing - ANSWER an appliance connected to the plumbing that uses energy to
perform its function, such as a clothes washing, dish washing machine, food-waste disposer, or
a water heater.
Arm, shower - ANSWER the generally horizontal pipe that connects the shower riser to the
shower head; usually curves down down at about a 30 degree angle near shower head.
Backflow - ANSWER the flow of a contaminate from an unintended source into the water
supply system. See Backpressure and Backsiphonage.
, Backflow preventer - ANSWER a device used to prevent backflow into the water supply
system.
Backpressure - ANSWER an uncommon condition that can occur when the pressure at a
point outside the water supply system is greater than the water supply system pressure.
Example: the weight of water in a swimming pool located above the water supply system pipes
can create enough pressure to force swimmimg pool water back into the water supply system
pipes.
Backsiphonage - ANSWER an uncommon condition that can occur when there is negative
pressure in the water supply system pipes; contaminants can be sucked into the water supply
system pipes. Backsiphonage usually occurs because of a sudden loss of water pressure
combined with rapid drainage of the water supply system pipes.
Backwater valve - ANSWER a device installed in the building drain pipe to prevent the flow
of sewage from a public sewer into the house. A backwater valve is recommended when
plumbing fixtures in a house are located below the nearest upstream manhole cover of the
public sewer.
Bend - ANSWER a fitting that changes the direction of flow in drainage pipes. Bends are
identified by the angle of the direction change, either by a fraction or by the number of degrees
of the direction change. Common bends include: 90 degrees (1/4 bend), 60 degrees (1/6 bend),
45 degree (1/8 bend), 22 1/2 degree bend (1/16th). The fraction describes how much of a 360
degree circle that bend angle sweeps. See Elbow and Sweep.
Branch drain (fixture branch) - ANSWER a pipe that receives material from two or more
fixture drains or from other branch drains; branch drains are usually horizontal pipes that may
have some vertical sections; a branch drain usually flows intoa stack or into a stack or into a
building drain.
GUIDE 2026/2027 COMPLETE QUESTIONS
WITH VERIFIED CORRECT ANSWERS || 100%
GUARANTEED PASS
Hydronic heating - ANSWER a heating system that circulates hot liquid or steam through
pipes; the pipes may be installed in the floor, ceiling, or wall, or may serve radiators or similar
devices.
Manifold (vent connector) - ANSWER a type of vent connector in which two or more vent
connectors are joined together before being connected to the vent.
Vent (combustion) - ANSWER the final vertical component in a vent system; this term most
accurately describes manufactured products such as metal pipes.
Vent (connector) - ANSWER a component that conducts combustion products from a fuel-
burning appliance to a vent; vent connectors are single-wall or double-wall metal pipes.
Vent system - ANSWER a passageway that conducts combustion products from a fuel-
burning appliance to a point outside the house; thevent system begins at the appliance draft
hood or flue collar and ends outside the house; the vent system consists of a vent or Chimney
and a vent connector, if one is used.
1/2 Bathroom (half bath) - ANSWER a bathroom with a sink and a toilet; also called a
powder room.
,3/4 Bathroom - ANSWER a bathroom with a sink, toilet, and a shower, but no bathtub
Aerator - ANSWER a device that introduces air into a water stream, usually attached to the
outlet of sink and lavatory faucets.
Adapter - ANSWER a fitting that allows connection of different pipe types or different pipe
sizes.
Air Admittance Valve (AAV) - ANSWER an air pressure operated one-way valve used in place
of an atmospheric plumbing vent; this device is different from a check (cheater) vent which
contains a spring loaded gasket and is not approved for use in site-built houses in most
jurisdictions.
Air gap - ANSWER the vertical distance between the discharge opening of a water supply
fixture, such as a faucet, and the flood rim level of a fixture such as a sink; an air gap is one
method of preventing a cross connection between the water supply and drainage supply.
Appliance, plumbing - ANSWER an appliance connected to the plumbing that uses energy to
perform its function, such as a clothes washing, dish washing machine, food-waste disposer, or
a water heater.
Arm, shower - ANSWER the generally horizontal pipe that connects the shower riser to the
shower head; usually curves down down at about a 30 degree angle near shower head.
Backflow - ANSWER the flow of a contaminate from an unintended source into the water
supply system. See Backpressure and Backsiphonage.
, Backflow preventer - ANSWER a device used to prevent backflow into the water supply
system.
Backpressure - ANSWER an uncommon condition that can occur when the pressure at a
point outside the water supply system is greater than the water supply system pressure.
Example: the weight of water in a swimming pool located above the water supply system pipes
can create enough pressure to force swimmimg pool water back into the water supply system
pipes.
Backsiphonage - ANSWER an uncommon condition that can occur when there is negative
pressure in the water supply system pipes; contaminants can be sucked into the water supply
system pipes. Backsiphonage usually occurs because of a sudden loss of water pressure
combined with rapid drainage of the water supply system pipes.
Backwater valve - ANSWER a device installed in the building drain pipe to prevent the flow
of sewage from a public sewer into the house. A backwater valve is recommended when
plumbing fixtures in a house are located below the nearest upstream manhole cover of the
public sewer.
Bend - ANSWER a fitting that changes the direction of flow in drainage pipes. Bends are
identified by the angle of the direction change, either by a fraction or by the number of degrees
of the direction change. Common bends include: 90 degrees (1/4 bend), 60 degrees (1/6 bend),
45 degree (1/8 bend), 22 1/2 degree bend (1/16th). The fraction describes how much of a 360
degree circle that bend angle sweeps. See Elbow and Sweep.
Branch drain (fixture branch) - ANSWER a pipe that receives material from two or more
fixture drains or from other branch drains; branch drains are usually horizontal pipes that may
have some vertical sections; a branch drain usually flows intoa stack or into a stack or into a
building drain.
