Water bills are set to rise above inflation in some areas in the next five years, squeezing household incomes.

All water companies must submit their pricing plans to regulator Ofwat by noon today and several have already outlined the extent of their rises.

Thames Water, the largest water company, said it would invest £6.5 billion overall in the next five years.

Bills will go up three per cent over inflation, Thames Water added; however, by 2015, on average, customers “will still be paying less than £1 a day for all their water and wastewater needs”.

Welsh Water has promised “no real increase in average household bills after 2010 – the average bill for drinking water and sewerage will stay at around £390 per household or just over £1 a day, before adding on general inflation”.

The firm will also invest £1.5 billion in improving the system over the period.

Northumbrian Water has said bills are expected to rise 1.3 per cent above inflation in the next five years, while United Utilities does not anticipate bills rising faster than incomes.

The increases are not as high as other utilities – British Gas recently announced a 35 per cent increase in gas prices while EDF Energy recently raised its prices by 22 per cent for gas and 17 per cent for electricity.

However, any further pressure on household income will be unwelcome and Ofwat will be expected to scrutinise the plans carefully before giving its approval.