Air-lock – air trapped in pipes, causing a reduction or complete stop in the flow of liquid.
Adaptor – device that fits different types of pipes together.
Back-siphon – a condition where the flow of liquid is reversed and siphons back towards the source, which can cause contamination of the source.
Bar – the unit that water pressure is measured in.
Bleed valve – a valve that releases air from the central heating system.
Cistern – a water tank that maintains a back-up supply of water for the toilet, and prevents back-siphonage into the mains.
Combination boiler / Combi boiler – a device which combines a domestic water heater and a central heating water heat exchanger, and heats water on demand.
Coupling – a device that connects two pieces of pipe.
Fixture – a broad term for apparatus that serve in the supply or disposal of water, e.g. sinks, tubs, basins or toilets.
Flange – those often referred to in plumbing include the Surrey flange and the York flange which fit onto the top of a hot water cylinder and allow the hot water to be drawn away from the tank, without any air. The Essex flange serves the same purpose but is fitted into the side of the hot water cylinder.
Grey water – waste water from domestic processes.
Hot water cylinder – insulated hot water tank, usually stores water under pressure.
Immersion heater – an insulated electric resistance heater that sits inside a hot water cylinder and heats the water.
Power shower – a shower incorporating a device that increases water pressure, thus using more water but creating a more powerful spray.
PVC – PolyVinyl Chloride – plastic used for water supply pipes.
Trap – section of the drain which holds water, creating a seal that stops fumes from waste travelling back into the house. The U-bend on the toilet is an example.
Vent pipe – pipe that allows the release of air or water from hot water system