Customers are being urged to use water wisely during a heatwave expected to place even more pressure on supplies.

Affinity, which supplies parts of Hertfordshire, north Essex and Tendring, says the increase in consumption of up to 40 per cent due to Covid-19 and unseasonably dry weather in May has led to a level of demand it has never seen in its 130-year history.

It says groundwater levels are still high for the season, but during the previous heatwave in May water use increased by 108 million litres a day – putting record levels of stress on supplies.

The additional 108 million litres of water a day it has put into the system is equivalent of supplying 400,000 extra customers.

But with temperatures high, even more pressure on supplies is expected.

It is now asking people to save water where they can to help get through the summer including avoiding sprinklers and hosepipes, as well as only using the dishwasher and washing machine when they are full.

The same picture is repeated in other parts of Essex.

Essex and Suffolk Water has said it has seen a 30 per cent increase in demand for its supplies during the coronavirus crisis and that while its reserves are currently satisfactory, customers should use water wisely.

An Affinity spokesman said: “Despite the wet winter and groundwater levels being high, water usage increased by 108 million litres a day during the last heatwave, putting pressure on our network. No ban has been put in place, we are just asking people to be mindful with their water use.”