Plumbing Terms - Glossary of Plumbers Terminology

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ABS Pipe

Acrylonitrile Butadiene Styrene (ABS) Pipes are rigid plastic pipes with superior range of performance values used for drain, waste, and vent lines. ABS pipe and fittings were originally developed in the early 1950s for use in oil fields and the chemical industry. In 1959, John F. Long.

ABS pipes and fittings are highly lightweight, only half the weight of aluminum pipes and fittings and one-sixth the weight of steel pipes – reducing transportation, handling, and installation costs. ABS pipe and vent lines are extremly durable with high tensile and high impact strength.

Access Panel

In the plumbing business wit an access panel is a covered opening in a wall or ceiling near a fixture that allows access for servicing a plumbing or electric system. After finishing a wall in your home you might have covered some pipes or valves that you will need access to in the future. The most problematic would be a water shut off valve that should be accessible. This is why you need to install a plumbing access panel. Access Panels come in a wide variety of shapes and sizes.

Adapter Fitting

In the plumbing industry an Adapter fitting is a fitting that joins two different types of pipe together, or joins threaded to non-threaded pipe ends, such as ABS to cast-iron, or threaded to non-threaded they come in Aluminium, (Stainless) Steel, Brass, Bronze & Nickel. Male adapter fittings are widely used to connect tubes and pipes to male pipes and tubes and are available in both inch as well as metric designs and specifications.

Air Admittance Valve

an Air admittance valve or AAV is a negative pressure-activated, one-way mechanical vent, used inside a plumbing system to eliminate the need for conventional pipe venting and/or roof penetrations.

A discharge of wastewater causes the Air Admittance Valves to open, releasing the vacuum and allowing air to enter plumbing vent pipe for proper drainage. Since Air Admittance Valve will only function under negative pressure situations they are unsuitable for all venting applications, such as venting a sump, where positive pressures are created when the sump fills.

Air Gap

An Air Gap in the plumbing trade is a device that is mounted to the back of a kitchen sink and connects the drain line between a dishwasher and disposer to allow the dishwasher to discharge freely into the disposer while preventing contaminated water from siphoning back into the dishwasher.

Angle Stop

An angle stop is the angled valve that is located between the fixture and the water pipes, and works as a shutoff valve. This valve is perpendicular to the pipe, positioned next to the fixture, and designed to be an emergency stop for the fixture's water supply.

Anti-Scald Valve

An Anti-Scald Valve is a shower mixing valve that automatically maintains balance between incoming hot and cold water supplies by immediately regulating fluctuations in pressure. As a result, temperature remains constant, though the outlet pressure may drop. Also called pressure-balanced valve.

Backflow Preventers

A Backflow Preventer does just as its name implies, they prevent backflow. Vacuum breakers and other backflow prevention systems are designed to stop gray/dirty water from potentially siphoning back into the water supply and contaminating the fresh water. A typical backflow assembly consists of shut-off valves and test cocks and must be tested each year.


A ballcock is a fill valve that controls the flow of water from the water supply line into a gravity-operated toilet tank. It is controlled by a float mechanism that floats in the tank water.


In the plumbing trade bleeding means to drain a pipe, tube, or hose of excess air by opening a valve at the end or systematically removing the air by force or suction.To remove the air inside your central heating system that has gotten trapped you need to bleed your radiator. Air in a radiator will rise to the top forming a pocket of air and stopping the hot water from getting to it, when there is too much air inside your system it will prevent it from heating properly.

Blow bag

Blow Bag

A blow bag is a device used for drain-cleaning, it is made of a rubber bladder with a hose fitting and a nozzle on the other end. The blow-bag needs to be attached to a water hose and inserted into a clogged drainpipe. When the water is turned on it will fill the blow bag and it expands gripping the pipe. The blowbag releases pulsating bursts of water through the nozzle forcing the water to clear the clog.

Branch vent

The branch vent is connected to the main vent, this pipe serves two or more fixture vents. The branch vent and the fixture vent should be run to a height above the overflow level of the fixture being served. This prevents sewage from draining through the vent line if the fixture waste branch gets clogged.

Building Sewer Service

Building sewer service is a general term that includes both sanitary or storm water drainage piping located within the property line that extends from at least one foot outside the building footings to a legal point of disposal. It does not include the mains of a public sewer system, or a public sewage treatment or disposal plant.

Building Water Service

Building water service is a general term that refers to the pipe from the water main or other source of water supply to the water distribution system of the building served. The water service pipe primarily includes all potable water supply located prior to the connection with the water meter inside the building.

Cap Fitting

In the plumbing trade with a cap fitting or cap is meant a type of pipe fitting, often liquid or gas tight, which covers the end of a pipe. A cap has a similar function to a plug. cap fittings are designed to attach over the outside of a tube end to dead-end the flow. A plug is inserted into the end of hose or tubing to dead-end the flow. Attachment techniques include welding, push-fit, brazing, adhesives, and threading.In plumbing systems that use threads the cap has female threads.

Catch Basin

A catch basin is a device that receives storm water drainage from an outside surface area. They are usually located in parking lots or in areas where the removal of storm water buildup is desirable. The catch basin is a part of a sewer system or storm drain that is designed to trap debris, preventing it from entering the drainage pipes.


A centerset is a type of faucet that has combined spout and handles, with the handles 4 inches apart - center-to-center. A single-handle faucet installed on 4 inches center-to-center faucet holes is also called a centerset.

Clean Out

Clean Out is a term used in the plumbing business to refer to the access to the sanitary or waste lines in order to be able to clean them out if they were clogged.