The declaration of severe drought is not linked to current rainfall, but to reservoir levels.
When making its recent assessment, the Environment Agency (EA) concluded that these levels have been significantly depleted by the South East experiencing its driest April to September in over a century., external
Specifically, the government said the change to severe drought status had been prompted by concerns for two major reservoirs, Ardingly in West Sussex and Wimbleball in Somerset.
Ardingly serves 280,000 customers across East and West Sussex.
On 14 October, South East Water said the reservoir was 19.4% full. A day later, severe drought was declared.
The latest reading reveals that Ardingly is 17.1% full, prompting the water company to reduce the daily volume of water released from the reservoir into the River Ouse to protect drinking supplies.
According to research published by the EA and the Department for Environment, Food and Rural Affairs in September, England needs 120% of its typical rainfall over the next seven months, external for all areas to be considered out of drought.