Water companies are urging consumers to save water this winter after an exceptionally dry year in some areas raised the spectre of restrictions next spring.
South East Water said the dry weather meant it could not rule out having to apply for drought permits to allow it to take more water from local rivers to top up reservoirs, or even imposing water restrictions next spring.
The company said its two reservoirs in Sussex were only a third full and groundwater sources were below average for the time of year, particularly on the Seaford coast and in West Kent and East Sussex, after the driest 12 months since the drought year of 1976 in the south east region.
South East Water said the traditional refilling of water resources from autumn rains had been delayed this year in the region, with less than two-thirds (60%) of the average rainfall in September and less than a third (30%) in October.
Meanwhile Thames Water said that while there was "no immediate problem" with its water supplies, below average rainfall this winter could pose difficulties.
Both companies are calling on consumers to do their bit to conserve water, for example by taking simple steps such as turning off the tap when brushing their teeth.
The warnings come after Anglian Water became the first water company in almost a decade to apply to the Environment Agency for a drought permit in winter, which would allow the company to take extra water out of the River Nene in the east of England to top up its Pitsford Water reservoir in Northamptonshire.
Lee Dance, head of water resources at South East Water, said: "The unseasonably warm, dry weather we're continuing to experience has delayed the start of the traditional period when rainfall refills both our reservoirs and underground sources, giving them a much needed boost before next spring and summer.
"Our underground sources in particular are crucial as they provide 75% of all our water supplies, and rely on that rainfall to fill them up."
He said the company had been monitoring the situation and fine tuning the water supply network to move water around the Sussex area, which has helped - as had the small amounts of rain received recently.
But he said: "It is prudent to plan ahead and make sure we do everything we can to secure supplies for our customers next year, so that does mean having to plan for possible droughtpermits and water restrictions."
Thames Water's sustainability director Richard Aylard said: "There's no immediate problem, but we're watching the situation very carefully.
"We do rely on winter rainfall, and last winter was dry, the summer has been quite dry and if we get a second dry winter, that would be a problem."
He said: "The last thing we want to do is impose restrictions," adding that the company wanted to encourage voluntary efforts by consumers to save water now.