A water company is warning that some of its sources remain very low despite the wettest summer in half a century.

South East Water said groundwater levels are still recovering from record lows earlier this year and some of the firm’s deepest aquifers remain very low.

The company said it would be hoping for rain to restore the groundwater sources, or aquifers, which provide three-quarters of its supply.

The firm, which provides water for 251,000 homes in Sussex, said autumn and winter rainfall is vital to refill groundwater sources which remained in mild to moderate drought. The company announced better news with unprecedented high levels of water in its reservoirs, which remain full after the damp summer.

Southern Water, which has 800,000 Sussex customers, also confirmed that the recent wet weather had left its reservoirs in a healthy position.

Bewl Water in Kent is just below 80% full compared to just 41% in February while Weir Wood near Forest Row is now at almost 90% capacity.

However, reservoirs account for less than 10% of Southern Water’s supply and the firm confirmed that some of its underground sources, which account for more than two-thirds of supply, are still below average.

Brighton, Worthing and Littlehampton areas are served purely by aquifers.

Sussex huddled under 276.6mm of rain between June and August according to Met Office figures, the largest amount of summer rain since 280.8mm fell in 1960.

Lee Dance, head of water resources and environmental at South East Water, said: “While restrictions have been removed and our water resources are in a much better place than they were, we must be prudent and are asking our customers to still do their bit to use water wisely, especially if we have another dry autumn and winter.”

A Southern Water spokesman said: “Our aquifers, which account for 70% of the water we supply to customers, have been topped up by the wet summer.

“However, some of the aquifers are slightly below average for this time of year due to the previous two dry winters.

“We are now entering what is known as the recharge period when winter rain refills aquifers which requires significant autumn and winter rainfall.”