AS BRITAIN faces a miserable summer of hosepipe bans and drought, households in some of Japan’s most densely populated cities are to be “punished” for saving too much water.

The national drive to cut down on water usage — galvanised by having the 1997 Kyoto Protocol on the environment signed on its doorstep — has been a catastrophic success.

A drop in consumption of up to 10 per cent over the past five years has shocked even the water authorities and several plan to impose an emergency 20 per cent price rise next week to protect their revenues.

Unlike Britain, Japanese water boards are tacitly hoping that the conservation trend reaches a plateau soon.

“The Government cannot, of course, tell people to use more water but there is rising concern over how far the average monthly water bill might fall,” a senior member of the Government’s committee on natural resources said.

The concern is financial and, say experts, exposes the legacy of Japan’s worst pork-barrel excesses. The water boards have spent the past two decades in an expensive orgy of dam construction and river management.

Even last year, amid calls from the Ministry of Finance to reduce the number of public works projects, there remained 200 dam projects on the go, sucking about 400 billion yen (£2 billion) from the public purse. Seven years ago the number was twice as high.

The Government, via the water boards, has borrowed heavily to finance the spree and long-term payment plans to the dam builders were based on the stability of revenues.

Kazuhiko Arita, the leading Japanese expert on the water industry, believes that the country has undergone an overnight change of mindset and become less wasteful of water.

“The use of tap water is decreasing everywhere. Now we have to pay for the fact that the country based its planning on the excessive demand forecast and kept building completely useless dams.”

Sei Kato, of the Ministry of Health and Welfare, admitted that the burden of paying for all the dams and other engineering projects was catching up with the water boards, but insisted that the projects were all undertaken to ensure stable supplies. The local boards have also spent heavily on maintaining the system itself: total leakage in metropolitan Tokyo in 2004 amounted to about 4.8 per cent, and the authorities believe that this can be reduced to 4 per cent by the end of this year.

Unfortunately for the Government, the need to meet loan payments coincides with a surge of environmentally conscious product development by the country’s biggest manufacturers of white goods. Sharp, Matsushita and Sanyo have all based recent marketing on water efficiency, and the buying public has been hooked.

Many houses filter the water as it leaves the kitchen tap — a process that usually wastes a lot of water because the filters empty themselves every two minutes. A new version made by Panasonic stores the water for ten minutes, and manages to save each household a tonne of water a year.

Most striking has been the steep rise in the use of dishwashers. Where ten years ago the machines were a relative rarity in Japan, they have now become commonplace. In the days of hand-washing the pots and pans, Japanese would tend to leave the taps running and got through about 150 litres a day on washing-up. The average dishwasher does the same job with about 10 litres. The dishwasher boom has also coincided with technological advances in the science of lavatories. The two biggest bathroom equipment makers have developed lavatories that use six litres of water per flush — half the amount used in 2001. Even more water is saved because 80 per cent of lavatories in homes have as standard a sink on top of the cistern, which allows the water that would be refilling the system anyway to be used for handwashing.

An Inax spokesman explained that the eco6 lavatory will save a family of four about a bath full of water every two days — the equivalent of about 45,000 litres a year.

Southeast England: usage up 50 per cent

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