A detailed study of household hygiene habits has led economists from Leicester University to predict that domestic water use in south and eastern England will rise by an average 40 per cent over the next 30 years and peak demand could go up by as much as 80 per cent.

In unpublished research being conducted for the Department of the Environment, Paul Herrington has looked at the effects of water use assuming a slight climate change of plus one degree Celsius in the period up to 2021. His findings will alarm the water companies currently struggling with drought conditions because even without any climate change peak domestic use is expected to rise by 65 per cent.

Mr Herrington's detailed breakdown of domestic and industrial water use into the next century points to ever rising demands being placed on stretched water resources. Increased showering and lawn irrigation were likely to be the most significant changes resulting from the warmer climate. "The nature of water use is going to change radically and it is these 'luxury' uses of water which are likely to grow while basic water use stands still," he said.

Important questions about catering for such increased demand - either by simply supplying customers with more water or by more difficult measures such as demand management - must be faced, according to Mr Herrington. He said: "The case for metering can certainly be made on efficiency and environmental grounds but equity is obviously more complicated." Currently 7 per cent of households in England and Wales are metered.

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In collecting his data on water use Mr Herrington took into account the proportion of households possessing appliances such as washing machines, dishwashers, showers and so on, the frequency with which they were used and the amount of water consumed.

Water consumed for clothes washing was expected to fall significantly over the period, since manufacturers of washing machines revealed that by 2021 the average cycle would use 75 litres of water compared to the current average 100 litres. Handwashing is also predicted to decline from the current 15 per cent of households regularly handwashing to 3 per cent by 2021.

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Showering was also examined and while an average shower used just 30 litres of water compared to 80 litres for a bath, Mr Herrington pointed out that people tended to shower far more frequently than bathe. Power showers were another factor since they used twice as much water as ordinary showers. "Given these indicators we must ask whether it is right to continue supplying water while conveying the message to customers that it is free," Mr Herrington said.