The south east of England is now in a state of drought, the Department for Environment, Food and Rural Affairs has said.
The region joins parts of eastern England which have been drought-afflicted since last summer, with some reservoirs, rivers and groundwater aquifers in the South East well below normal levels after two dry winters.
The state of drought in the region was declared after the Environment Department convened a summit of water companies, farmers and wildlife groups on Monday to discuss potential water shortages in England.
Following the summit, Thames Water warned that there was a high chance of water restrictions such as hosepipe bans this summer unless there is significant rainfall or customers use less water.
Some rivers and groundwater levels are lower than during the drought of 1976. In the South East, Ardingly reservoir in West Sussex and Bewl in Kent are around two-fifths of their normal levels, according to the Environment Agency.
Southern Water has applied for a drought permit to help refill Bewl reservoir, while late last year South East Water was granted a drought order to help refill Ardingly.
Anglian Water has also been issued with two drought permits to refill two of its reservoirs.
Speaking after the drought meeting at Defra, Environment Secretary Caroline Spelman said: "Ensuring we have enough water this summer is vitally important, and that is why I called the summit.
"Drought is already an issue this year with the South East, Anglia and other parts of the UK now officially in drought, and more areas are likely to be affected as we continue to experience a prolonged period of very low rainfall.
"It is not just the responsibility of Government, water companies and businesses to act against drought. We are asking for the help of everyone by urging them to use less water and to start now."