Glossary of Plumbing Terms


Access Panel
An access panel is an opening in a wall or ceiling near a plumbing fixture. An access panel offers access to work on plumbing or electrical systems.

Angle Stop
An angle stop is a shutoff valve between the water supply and a plumbing fixture. It is used to shut off water flow while you repair the connected item.

Anode Rod
An anode rod is located inside a water heater. The anode rod protects the water tank from corrosion caused by magnesium or aluminum.


Backwater Valve
A backwater valve prevents sewage from reentering a home.

Ball Check Valve
A ball check valve is a type of backflow valve or preventer. The ball check valve is placed on a water line to direct water flow in only one direction.

The ballcock controls the flow of water in a gravity operated toilet tank. When the toilet is flushed, the circular float will drop and open the ballcock. This results in water flowing into the tank. As the water rises, the float rises to the level that shuts of the ballcock.

A branch is any secondary part of a drain system. It's also referred to as the lateral line.

Branch Vent
A branch vent connects vents with a vent stack.


Check Valve
The check valve is a type of backflow preventer. The check valve is installed on a pipe to allow water flow in only one direction.

Cleanout Plug
The cleanout plug is in a trap or drain pipe. A cleanout plug offers access to a drain line for clearing any blockage in a pipes.

A synonym for a toilet, also referred to as a "water closet."

Closet Auger
A closet auger is a flexible rod that is used to access a toilet's trap to remove any clogs.

Closet Bend
A closet bend connects the closet flange to the toilet's drain.

Closet Flange
A closet flange is a ring that anchors the closet bend to the floor. The closet flange also includes bolts that secure the toilet in place.


A diaphragm is a flexible membrane that helps regulate water flow and build up within a valve.

Dip Tube
A dip tube sends cold water to the bottom of a water heater tank.

Drip Leg
A drip leg, also known as a "sediment trap", is a pipe installed at the lower segment on a gas line. The capped off section collects condensation and any debris.


The escutcheon is a protective cover under the faucet handle that masks the fixture's hole.


The fall, also known as flow or pitch, refers to the slope needed to create proper drainage in pipes.

A fixture refers to the plumbing device that provides water and/or disposal. Common fixtures in plumbing are toilets, sinks and showers.

Flapper Valve
A flapper valve connects the water tank and toilet bowl. When the flapper valve opens, water flows from the tank into the bowl.

Float Ball
A float ball is the plastic ball attached to the ballcock. The rise and fall of water in the tank is determined by the float ball's placement.

Floor Flange
A floor flange, also known as a closet flange, connects a toilet to the sewer line.


Gas Cock
A gas cock on a main gas line allows for the gas to be shut off.

Gate Valve
A gate valve controls the flow of liquids in pipes.

Gravity Operated Toilet
A gravity operated toilet relies on downward pressure of water in a toilet tank to flush. Gravity operated toilets usually have ballcocks in their tank.

Gray water
Gray water is any waste water that comes from fixtures other than toilets.


Horizontal Branch
A horizontal branch runs from plumbing fixtures to a waste stack.

Horizontal Run
A horizontal run is the distance liquid travels from the entry point and exit of a pipe.

Hose Bib
A hose bib is a common outdoor faucet.


Main Line
The main line supplies water from the water company's meter at street level to the branch pipes around a home or other building.


A nipple is a short pipe that connects couplings and other fittings.


Power Flush System
The power flush system compresses water to provide a pressurize flush. This type of system is usually found in business and commercial buildings.

PRV or Pressure Reducing Valve
PRV, or pressure reducing valve, is a special valve that is installed directly on the main water line. The PRV constrains the amount of water entering from the water company's supply line to normalize water pressure for home use.

PVC pipes are sturdy plastic pipes that are used for drainage, waste and vent systems.


Rim Holes
Rim holes are a series of small holes around the toilet bowl. Water flowing from the rim holes washes over the surface of the bowl to refill the toilet bowl.


Saddle Valve

A saddle valve is a mounted pipe run by a clamping device. A saddle valve is used to make quick connections between low-demand devices.

Septic Tank
A septic tank is a small sewage treatment system for homes with no connection to local sewage lines. Septic refers to the bacteria that decomposes the waste inside the tank.

Straight Stop Valve
A straight stop valve is a straight shutoff valve used to close off the water supply during repairs.

Sump Pump
A sump pump is used in basements that often flood. The sump pump sits in a pit that accumulates the water where it pumps the water outside the home.

Supply Line
A supply line is a metal or plastic line that carries water directly from the main line into a plumbing fixture.


T&P Valve or Temperature and Pressure Valve
The temperate and pressure relief valve is used to safely release excess heat or pressure in a water tank.

A tailpiece is a pipe that runs between a fixture and a trap.

The trap is a curved section of drain line that prevents sewer odor from entering a home or other building. All plumbing fixtures have a "P" trap, except for a toilet that has an "S" trap.

A trapway connects the toilet bowl to a waste outlet. The size of the trapway, also known as the passageway, influences clogging.

Trip Lever
A trip lever is the flush handle and actuating arm on a toilet tank. The trip lever is attached to the flapper, which results in the toilet flushing. The trip lever can also refer to the drain in a tub.


A vent is a pipe that allows air into the drain system.

Vent Stack
A vent stack, also known as a stink pipe, releases gas and odors outside the home or other building.


Water Hammer
The water hammer is a loud noise and vibration associated with pipes being turned on or off. Water hammer is caused by a sudden surge, or halt, of water in the pipes.

Plumbing Clogs - What You Must Know