Consumer bodies have criticised the increases

Ofwat's announcement on Thursday means South West Water (SWW) will have the highest average bill by 2009-10, - �444 per year, up from the current �357.

Next year's rise, as expected, will be about 15% and the following two years will also see sharp increases.

SWW said the increases were needed to meet the company's obligations for improved sewerage and water pipes.

We are disappointed whenever charges have to rise Bob Baty, South West Water Chief Executive BBC Devon: Have your say on water bills

Maurice Terry of consumer body WaterVoice said millions of water customers would find the increases "neither affordable nor acceptable".

He said: "The government must act immediately to ensure that customers on low and fixed incomes receive effective help to pay their water bills, through the mainstream tax credits and benefits system."

Overloaded sewers

South West Water's Chief Executive, Bob Baty, said: "We are disappointed whenever charges have to rise, but the increases are necessary to enable us to deliver all of the obligations required of us."

Ofwat has said the increase is needed so pipes, sewers and treatment works can be maintained.

The body also said 3,000 schemes to improve rivers and coastal waters and 500 investigations to inform decisions on future and environmental protection would also require additional funds.

It also said it would need to spend money on alleviating internal flooding from overloaded sewers.