The drought which has hit parts of the UK this year could continue until next summer if the country suffers a dry winter, the Government has warned.
The warning came as South East Water applied to the Environment Department for a drought order to help refill Ardingly Reservoir, where levels of usable water are now at just 12%, to secure supplies for East and West Sussex.
Environment Secretary Caroline Spelman said there was a high risk that parts of the country will "almost certainly be in drought next summer" without sustained rainfall in the winter months to restore water levels hit by the extremely dry spring. She warned that water companies and the public needed to plan now for a potential drought in 2012.
The Environment Agency said the south-east of England was at a high risk of drought due to continued low rainfall, while central, eastern and south-eastern England were unlikely to see a full recovery from drought conditions in 2012.
Parts of the rivers Colne, Nene, Trent and Kennet are nearing their lowest ever recorded levels for November, a report by the agency revealed.
The warning comes after Anglian Water was issued with a drought permit allowing it to refill two of its reservoirs from rivers now in a bid to avoid hosepipe bans next year. And Severn Trent Water will have to apply for a drought permit to refill the Tittesworth reservoir if it is not refilled naturally by spring next year, the Environment Agency said.
Lee Dance, head of water resources for South East Water, said: "Faced with a worsening drought situation, and with no sign of significant rainfall and customer demand for water continuing, it is vital we take immediate steps to protect Ardingly Reservoir and our customers' water supplies."
He said the short-term impacts on the River Ouse would be minimal but measures had been put in place to protect the water environment.
Mrs Spelman said: "Droughts are not new but we may face a future with less rainfall and less certainty about when that rain will fall. That is why we will shortly be setting out our plans to ensure we have a safe and secure water supply in the future."
Environment Agency chairman Lord (Chris) Smith said: "Today's Environment Agency report urges all water users - especially farmers, businesses and water companies - to plan carefully how they store, use and share water. As we have seen over the spring and summer, drought has serious impacts on the environment, especially for wildlife."