Handset - A shower head attached to a shower hose.

Horizontal Outlet - The outlet at the back of the WC is perfectly horizontal; compared with a P-Trap outlet which slopes down at an angle of 14 degrees and an S-Trap outlet which turns vertically downwards.


Legset  -Usually for an acrylic bath. Made from steel with adjustable feet and attached to the bath frame (which itself may be made of steel or wood) to support the bath.

Lever -The handle used to operate a siphon flushing device

Front lever - found on the front of the cistern or bathroom furniture. May sometimes be fitted to the left or to the right. 
Side lever – found on the right hand wall of the cistern


Manual mixer shower - In this mixer unit, hot water direct from a boiler or hot water tank is blended with cold water to deliver a shower at the temperature controlled by the user. Simple mixers have the disadvantage in that the final water temperature can vary if incoming water varies in both temperature and pressure. Generally they give a higher flow rate than an electric instantaneous shower.

Membrane - Material used in the tanking kit. Usually made from plastic and forms part of the waterproof seal in a wet room.

Mixer taps - Single bodied mixer taps blend the hot and cold water in a single spout. The spout may have a single flow (where the hot and cold water is blended within the body of the mixer) or a dual flow (where water remains separate and only blends after it has left the spout opening). Mixers may have two conventional washer valves (one for hot and one for cold) or they may have a more complex ceramic disc valve which has a single handle. This will move up and down to control the amount of water flow, and from side to side to control the temperature.


Offset corner bath - Similar to a corner bath but the two sides are of unequal length.


Panel - The front side or end of a bath in wood or plastics material. Designed to complement the shape and style of the bath and to hide ugly fittings and pipework.

Phased shutdown - Applicable to instantaneous electric showers. When the shower is switched off it will continue to run for a few seconds while cold water passes through the heating coils to remove hot water and reduce the incidence of limescale build up.

Pillar taps - These are individual tap units which control the hot and cold water supply to a washbasin or bath. The taps may have conventional washer valves or modern ceramic discs. Pillar taps require two holes in the washbasin or bath. Washbasin taps have ½ inch inlets and bath taps have ¾ inch inlets.

Pop up waste - A lever or rod situated in the body of the monobloc tap is used to lift or close (by means of rigid metal rods or flexible wires) a plug located in the washbasin or bath waste fitting.

Plumbing Systems - Gravity system – vented hot and cold water storage

Usually identified by: 

  • The presence of a hot water storage cylinder in the airing cupboard. 


  • The presence of a cold water storage cistern in the loft. 
  • Water is fed to the hot water cylinder from the cold water cistern. 
  • Water is fed to the cold water cistern from the incoming mains.
  • The cold water cistern should be at least one metre above the shower head for a satisfying shower otherwise a booster pump will be required to improve water pressure and water flow. 
  • This system is open or ‘vented.’


High pressure system – un-vented, mains fed, hot water storage 

Usually identified by: 

  • The presence of a hot water storage cylinder which has a special expansion vessel attached to it. 


  • There will be no cold water storage tank in the loft. 
  • Water is fed to the hot water cylinder by the incoming mains. 
  • This water is heated by a separate boiler or immersion heater.
  • Since the hot and cold water is under high mains pressure the shower will be a very satisfying powerful shower. 


Combi system – high pressure with no water storage

Usually identified by: 

  • No hot water cylinder in the airing cupboard 
  • No cold water cistern tank in the loft 


  • The presence of a 'Combi' or 'combination' boiler which heats water as it is required.. 
  • Provides hot water as and when it is required with no storage.
  • A shower pump cannot be added to a combi system.

Power shower - A water pump which is either separate from the controls, or an as an integrated unit, boosts the pressure of incoming water to provide a increased pressure and flow rate at the shower head. Used with gravity fed plumbing systems where water pressure is relatively low. Not suitable for use with a `Combi boiler'.

Pressure balancing shower - A manually operated shower mixer which blends hot and cold water but maintains a constant set temperature by reacting to fluctuations to the pressure of the incoming hot and cold water. Not to be confused with Thermostatic. Better control of water temperature than manual.

Push-button flush valve - This type of flushing device is common worldwide but has only permitted for use in the UK since 1999. When the button is pushed water flows out of the cistern to flush the WC pan. Push button valves may also be configured for dual flush.