Southern Water has applied to the Environment Agency for a “precautionary” drought permit to pump water into the Bewl Water reservoir – the largest stretch of open water in the South East of England.

The company said there had been “exceptionally low rainfall” during the winter of 2016-17 and during October and November 2017.

It said Bewl currently holds less than 43 per cent of its maximum 31,000 million litres capacity. Figures from 28 December 2017 show the Bewl reservoir level at 38 per cent.

The reservoir in Lamberhurst, near Tunbridge Wells provides water to hundreds of thousands of people across Kent and East Sussex.

Southern Water said it needs to act to “safeguard supplies” for customers and reduce the risk of needing to introduce “temporary restrictions” on people’s water use over the coming summer, such as prohibiting the use of hose pipes to water household gardens.

The company said the permit would allow it to refill the reservoir in the weeks up to 1 April 2018.

If approved, the drought permit for Bewl will give Southern Water “greater flexibility” to take water from the River Medway and River Teise and pump it into the reservoir to help boost its water level ahead of next spring and summer.

Southern said abstracting more water from the rivers would be a short-term measure to secure water supplies as the permit would only be valid until the end of March.

“We are applying for the permit now because taking water in winter is less likely to have any environmental impact, compared to the summer.

“It will aid us in getting the water to healthy levels of around 70 per cent full by the end of March along with winter rain,” the firm said.

Southern Water last applied to the Environment Agency for a drought permit in 2012.