Plumbing Terms - Glossary of Plumbers Terminology

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Lockshield Valve

A lockshield valve is fitted at the return side of each radiator and used to balance the system when it is first installed. Generally there is no need to adjust them once set (they are normally covered with a cap), if they are closed to allow for the removal of a radiator, count the turns to the off position so that they can be reset when required.

Low Level Cistern

A low level cistern is a tank that is mounted on the wall just above the toilet pan with a short flush pipe. Generally the cistern is operated by a lever mounted on the front of the tank or (more modern) a push button on the cistern top cover.


The main is the primary artery of supply of the water supply or drain system in which all the branches connect. In the case of drains, known as the Main Vent.

Main vent

The main vent is the pipe that runs vertically beside the soil stack. The branch and fixture vents are connected to the main vent, and through it each trap is supplied with air by the outside atmosphere. The main vent is connected to the outside either by being extended through the roof separately or by being run back into the soil or waste stack at a point above the highest fixture connection.


The wiring, plumbing and heating and cooling systems in a building; also the components with moving parts such as furnaces, plumbing fixtures, etc.


In the plumbing and piping trade, a nipple is a fitting that consists of a short piece of pipe that is usually provided with a male pipe thread at each end, for connecting to two other plumbing fittings. The length of the nipple is usually specified by the overall length including the threads. It may have a hex section in the center for wrench to grasp.

No-Hub Connector

A No-Hub Connector is a connector for no-hub iron pipe consisting of a rubber sleeve and a stainless steel band secured by hose clamps. A variation, a neoprene sleeve with two adjustable steel bands, is used for connecting dissimilar materials, as when connecting new plastic pipe to an existing cast-iron drainpipe.


Loosely woven hemp rope that has been treated with oil or other waterproofing agent; it is used to caulk joints in a bell and spigot pipe and fittings.

Overflow pipe

An overflow pipe is a pipe connected from a tank or cistern to discharge any surplus water into an area without causing damage, normally it will only come into use when there is a problem with your plumbing (i.e. a leaking valve etc).

Perk Test

A Perk Test is the test that is done to see how well the soil allows water to penetrate or perk. This test is done to see if a septic tank can be used in a particular location on a piece of property.


A plumber is a tradesperson who specializes in installing and maintaining systems used for potable (drinking) water, sewage, and drainage.

Plumbers Crack

The terms plumber's crack (Canadian, Australian and American English), "cofrinho" (Brazilian Portuguese), and builder's bum (British English) refer to the exposure of male buttock cleavage, especially on occasions of careless bending over.

Plumbers Putty

Plumbers Putty is a substance that that can be molded and shaped and is used to create a watertight seal around a faucet or drain pip. Plumber's putty is sold at at hardware and DIY centers around the country and is considered one of the most basic plumbing tools.

Pressure Balance Valve

A Pressure Balance Valve is a shower mixing valve that automatically regulates the balance between incoming hot and cold water supplies by immediately controlling the fluctuations in pressure. As a result,the water temperature remains constant, though the outlet pressure may drop a litlle. Also known as an anti-scald valve.

Pressure Test

Plumbers use a Pressure Test to check if it maintains a constant pressure. During the pressure test they pressurize the plumbing line and monitor the pressure inside.

Pushfit Connectors

In the plumbing trade with pushfit connectors are meant a type of plumbing connector which just push onto the pipework rather than using compression or capillary connectors - they can be made of plastic but are suitable for both hot and cold water - sometimes referred to as 'Speedfit connectors' (one of the early brands). Available as straight, 'T', elbow and other configurations.