PERSONAL WASHING ACCOUNTS FOR 33% OF HOUSEHOLD WATER USE

Most householders are aware that taking showers uses less water than having a bath.  However, power showers can use more water than a bath. Choosing the right type of shower can give householders the sensation associated with a power shower, whilst using significantly less water.

Showers that use more than 12 l/min require consent from the local water company under the Water Supply (Water Fittings) Regulations. Initiatives are underway to reduce sales of high use shower heads by reducing this threshold limit to 10 l/min.*1

Shower water use depends greatly on water pressure.  For showers using mains pressure (usually 1.5 to 2 bar), shower heads are available that provide the effect of a power shower but limit the volume of water used. Showers using pumped systems are regulated by the pump specification.  Some power shower booster pumps generate as much as 24 litres/minute*4, double that of a normal power shower.

The volume of water used by showers depends on a number of factors, as outlined in the Environment Agency “Conserving Water in Buildings”*3 including:

• The heating mechanism.  The warm up time for combination boilers and the length of pipe dead legs;
• Fixed/adjustable controls.  Separate flow and temperature controls, stability of combination-boiler temperature control and stability of plumbing system pressures; and
• Flow rate.  Spray pattern, mains pressure and variability, use of pumped systems and position of header tank.

House builders generally choose shower fittings with the performance of power showers due to customer demand.  Some manufacturers claim that their showers have the feel of power showers, while delivering a lower volume of water. 

Baths use approximately 80 litres of water each time they are used. Certain ‘water efficient’ baths are shaped to reduce the volume of use, but the frequency of their use is likely to be significantly lower than showers.  No water efficiency specification is to be applied to baths.