Water use through showering has increased in the UK and is predicted to double over the next 20 years.

Indeed, the trend for consumers to wash more than once a day using high-flow fittings has resulted in water and energy expenditure for showers exceeding that for baths.

This comes at a time when proposals by the Department for the Environment, Food and Rural Affairs recommend a reduction of UK water use from about 150L (39.6 gallons) per person per day to 120-130L.

A recent study by Liverpool John Moores University (LJMU) combined technical evaluation, a consumer focus group and home trials to examine water saving in the shower. The study assessed the main physical performance criteria of different shower types, customer attitudes to showering and the results of home trials using water-saving devices.

“We conducted the study in collaboration with United Utilities, a big water and sewerage infrastructure company in the North West of England,” says Dr David Phipps, who managed the project on behalf of LJMU.

“As part of its social responsibility program United Utilities was looking at water saving – particularly how it is affected by showering.

“The study aimed to establish three things: what people thought about water saving and showers; technical aspects of how the shower works and its influence on ‘the shower experience’, which is to do with water flow, distribution and droplet size and how it affects comfort; and which ways of restricting water flow work best in terms of the shower experience.

“For this last part we conducted tests in volunteers’ homes.”

The study recognized that water use varies greatly according to the type of shower used, and it aimed to investigate how clever shower design can meet the twin expectations of efficiency and performance.

It found that electric showers, which constitute 46% of installations, have typical flow rates of only 3-8L per minute (0.8-2.1gpm). Flows are inherently low and it is not usually possible to modify the showerhead or the flow, as this may damage the heating unit.

Mixer showers without pumps, and pumped showers, are increasingly popular but have heavier flows – in some cases up to 20L per minute (5.2gpm) – but these can be restricted by fitting a flow regulator or water-saving showerhead.

“The report found that mixer and pumped showers tended to use more water, electricity and carbon than washing by bath,” Phipps says.

“This was attributed the flow rates of these types of showers, and the fact that the frequency and duration of showering was much greater than for bathing because of the ease of taking a shower.