"We need to value and use water much more carefully," Benn told a news conference unveiling the government's new water strategy. "These pressures are going to get worse as the climate changes, the economy grows and the population increases."

Britons use an average of 150 litres of water a day or 52 tonnes a year for drinking, cooking, eating and washing. The aim is to cut that by 20 percent to 120 litres a day by 2030.

The current usage figure is the same as Finland, France and Luxembourg but well below Spain's 265 litres a day and well above Belgium's 108 litres.

While climate change will bring wetter winters to the British Isles they will not fully offset the reduction in water from the predicted longer, hotter and drier summers, Benn's Department for Environment, Food and Rural Affairs said.

Among the array of water-saving measures the government is looking at are household water meters which have been shown to cut consumption by around 10 percent, stopping leaks, increasing appliance efficiency and encouraging more thoughtful use.

The southeast, with the highest population density, is already classified as water-stressed and expected to become more so as numbers grow and rainfall declines.

But while climate change will cause droughts in some areas, it will also increase the frequency and intensity of rain storms such as those which caused floods across northern England last August, causing three billion pounds of damage.

Industry, Benn said, which has already taken action to cut usage and waste, must continue to improve efficiency.

The government would consult industry on removing phosphates from laundry detergents, which account for 10 percent of environmentally harmful water pollution.