Householders have been urged to take simple measures to save water, such as turning off the tap when brushing teeth or using a bucket of water instead of a hose.
A campaign on saving water was launched by the local authorities in the greater Dublin area yesterday, to coincide with Water Awareness Week which begins next Monday.
Minister for the Environment Dick Roche said rapid growth in Dublin had put a "huge strain" on the water supply system.
"Consumption [in the Dublin area] has increased to 500 million litres per day. That's an astonishing statistic," he said. "If people don't conserve water we will see shortages . . . and Government will have to provide more money to build reservoirs and to build additional capacity."
However, he said there was no proposal to change the law to allow for the introduction of domestic water charges.
Local authorities in Dublin, Kildare and Wicklow have been allocated €177 million to carry out works to old pipes and reduce the amount of water being wasted.
Deputy city engineer Tom Leahy said 12 litres of water was wasted every time the tap was left running during teeth-brushing. If even half the people of Dublin turned off the tap when brushing their teeth, nine million litres would be saved every day.
