Britain could face a water crisis if there is no significant rain in the next fortnight, the Environment Agency has warned.
Water companies are urging customers to conserve water
The agency said the east and the south were in particular need of rain to avoid a critical situation.
As the dry period continues, seven water companies covering the south east of England on Wednesday urged customers to conserve supplies.
Southern Water, Thames Water, South East Water, Mid Kent Water, Three Valleys Water, Folkestone and Dover Water and Anglian Water supply a total of more than 18 million customers in the driest part of the country.
Met Office figures show that south east England had the driest August and September since 1873, with only 27 millimetres of rain - just 23 per cent of the average of 119 millimetres.
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"It's generally been the driest nine months across much of the United Kingdom since 1921," said forecaster Nigel Boulton.
"In some areas its been the driest nine-month period on record."
He said some rain should fall in the next couple of weeks, but during this week some parts of central and eastern England may see very little rain.
The Environment Agency's head of water resources Ian Barker said the next few weeks "will be critical"
"If we don't [get reasonable rainfall] then the Environment agency will be monitoring the position very carefully, working with the water companies and advising the government on what steps the companies and the rest of us need to take in order to make sure we continue having water coming out of our taps, but also flowing through our rivers."
While the dry summer has contributed to colourful autumn leaves, farmers have reported new-sown seed failing to germinate.
Livestock are already being fed on winter stores because there is no pasture, farmers say.
National Farmers' Union cereals chairman Peter Kendall, a farmer in East Anglia, said the harvest benefited from the hot summer, but the lack of rain has ruined the beginning of the next season.
"We planted a lot of the oilseed rape in East Anglia while the combines were still running in the middle of August and September.
"A lot of that crop has now been written off. It has received no rain of any significant quantity.
"And the winter cereals that have been planted from the beginning of September onwards have also received no rain.
"We do need some rain pretty urgently. If we don't see some rain in the next three weeks, things will be looking pretty dire."