This new social phenomenon - the equivalent of panic buying groceries, candles, and other necessities in times of emergency - was highlighted by the independent Mid Kent Water Company.
Around 10,000 of its customers are without water, while supplies nationally are said to be good.
The company admits it wrongly programmed its computer model for water demand near Sevenoaks last week, resulting in supplies failing in several villages over the sweltering weekend. Water had to be taken to consumers by bowser and tanker.
But it believes the problem is being aggravated by some householders hoarding water, thus preventing the refilling of the underground reservoirs that keep the system running.
"It's panic storage," said the company's spokesman, Brian Clifford. "People are building up their own water stocks for fear of future cuts. I think they're putting in it the bath, in water butts in the garden, in all sorts of places. We appeal to our customers not to take any action that might cause others to suffer."
The company believes the hoarding is the reason for shortages yesterday in three Kent villages, Biddenden, Tenterden, and Charing. "The panic is spreading across the county," Mr Clifford said.
The problem began in the village of Plaxtol on Friday. Over the weekend it spread to West Kingsdown, Kemsing and Otford. On Saturday, as demand soared with the temperature, the company hired a plane to tow a banner reminding people they needed a licence to use a sprinkler. Water supplies failed at several farms, including one with 2,000 sheep, which had to be supplied by tanker.
Consumers were extremely angry, especially those who live in isolated houses. "I haven't seen any of these tankers and I find it difficult to get into the village in any case," said Jane Knight, 68, who lives five miles from Kemsing. "I have been without water all weekend. I haven't been able to wash or even flush the loo."
The company, which serves half a million people, hopes supplies will be back to normal later this week.
It is blaming its computer mistake on an incorrect weather forecast from the Met Office. "We were given a temperature forecast that was 10 degrees too low," Mr Clifford said. The firm is considering applying for a hosepipe ban.
The problem in Kent is an aberration, according to the Environment Agency and Water UK, the umbrella body for the industry. Both said supplies across Britain are healthy.
"Nobody is anticipating any problems over the summer," said Water UK yesterday after surveying its 29 member companies.
Giles Phillips, of the Environment Agency, said supplies were "generally pretty healthy". "Reservoir levels are mostly above 90 per cent, which is very good for this time of year. Ground water levels are falling, but only within the normal sorts of range," he said.Reuse content