Thousands of households have suffered water shortages this week during the summer's first prolonged period of hot, sunny weather.
Rocketing demand is to blame rather than any lack of water - there is plenty in reservoirs and underground aquifers after a wet winter.
But the deluging of lawns and flowerbeds with tapwater is straining distribution systems beyond their limits in parts of south-east England.
Water pressures drop and in some areas near the edge of the supply network - usually in villages and the countryside - there is now no flow at all for an hour or longer in the evening.
''The peak demand is the highest we've ever experienced,'' John Foxley, Southern Water's manager in Sussex, said. ''We're seeing a social and cultural change in which people see water as a right and where they regard watering lawns as equally important to other, more essential uses.''
The drought culture which existed several years ago, fostered by severe shortages, hose pipe bans and propaganda campaigns against wasteful water use, had long since evaporated, he added.
So Southern Water, which covers much of Kent, East and West Sussex, and Hampshire, is once again asking people to use water wisely. Lawns only need sprinkling once a week, not nightly. Letting the grass grow a little longer helps keep it green. And the best time to water is in the late evening - any earlier and much of it evaporates.
Thames, the largest water company, also reported that some of its customers outside London were suffering shortages due to excess demand. ''We'd ask people to show restraint and not do things like leaving sprinklers on overnight,'' said a spokesman.
The supply problems strengthen the case of those in the industry who argue for the spread of water metering. Experience indicates that there is usually a permanent reduction in water use when households pay for each gallon used, even if bills with meters are cheaper than those without.
Yesterday, Thames officially opened a huge new water storage scheme which uses a 40ft layer of sand beneath north London to hold up to 150 million tons - equivalent to one very large reservoir.
In winter, when there are ample supplies, surplus mains water is pumped into the aquifer below Enfield and Haringey, raising the water table. In summer that stored water is pumped out of the aquifer into the New River, an aqueduct built as a commercial venture 400 years ago to take fresh water from Hertfordshire into London. It flows down to Coppermills Water Treatment Works, at the southern end of the chain of Lea Valley reservoirs in east London.
The pounds 7m scheme uses 15 new boreholes along the New River, which descend as deep as 400ft through the sand into chalk below. The system keeps the water flowing in the river year round, which boosts the variety of fish and other life living in it.
n The National Rivers Authority, the Government's water watchdog, is this week fighting a water company's plans to drill a new borehole into an aquifer near Ashford.
The authority is asking a government-appointed inspector at a public inquiry to reject Mid Kent Water's application for the borehole between Charing and Lenham on the ground that it would lower the flow of the springs and streams that feed the Great Stour, thereby increasing pollutant concentrations in the river.Reuse content