Consumers in many parts of the country are facing soaring water bills, with some going up by more than four times the rate of inflation as the suppliers look to make big investments in their infrastructure and after a difficult period of drought.

People supplied by South West Water face the biggest rise, with charges for unmetered customers rising by 16% to £650 a year, or £378 for metered customers.

Big increases are also imminent for customers of Wessex Water, where charges are set to rise by an average of 9.47%, making an unmetered bill about £399 for the year, and United Utilities, in whose supply area the charges are rising by 8.27% to around £341.

The one area where charges will fall is in Tendring Hundred, Essex, where customers will see a 2.5% cut in the charges for their water and sewerage.

Ofwat, the regulator, which controls prices, said that the increases were necessary to enable the companies to make improvements to their infrastructure.

In many parts of the country, leakage repair projects have fallen behind schedule and Thames Water, for example, has had to invest an extra £150m in repair work for failing to meet its targets.