Severn Trent, which supplies water to the flood-stricken towns of Gloucestershire, is on course to make profits of nearly £300 million this year. The company told investors in the City yesterday that there was no reason to change its outlook for its financial year to March 2008 despite the floods.

The company’s announcement came as thousands of homeowners faced up to another two weeks without being able to bathe, flush lavatories or wash their clothes.

The company has made £1.1 billion profits in the past five years and last year handed nearly £580 million to shareholders. More than two million homeowners across the Severn Trent region have seen their water and sewerage bills rise by more than double the rate of inflation this year to £279, an increase of 5.7 per cent or £15.

As some waters began to recede, Hilary Benn, the Environment Secretay, announced a further £10 million in emergency aid yesterday and added: “This emergency is still not over and the River Thames continues to cause concern.”

The Environment Agency said last night that 800 homes and businesses in Oxfordshire had been flooded, including 570 in Abingdon. In Berkshire, Surrey and the London boroughs of Sutton and Lewisham 93 properties have been hit by flooding.

Engineers assessing the damage to the Mythe water treatment centre at the confluence of the Severn and Avon believe that it will take at least another week, or possibly two, to restore supplies.

The plant, which supplies drinking water to 140,000 homes in Cheltenham, Gloucester and Tewkesbury, was submerged for 48 hours at the height of the flooding, contaminating storage tanks, damaging the pumps and wrecking electrical switch gear. A further 10,000 homes in Stroud were left without water when a reservoir supplied by the plant ran dry.

Supermarkets in Cheltenham and Gloucester ran out of essentials, including bread and milk, nappies and baby food, as people stockpiled supplies, expecting shortages. In Gloucester, many residents complained that every bowser they visited had already been drained. Children were blamed for deliberately opening the taps on several and letting them run dry.

Tim Brain, the Gloucestershire Chief Constable, gave warning that anyone caught vandalising the bowsers would be prosecuted. He said: “If people are calm and patient there is enough water for everyone’s daily needs. But that is not normal daily needs – I am just talking about drinking, cooking and basic sanitation.”

Nearly 900 water bowsers were on site or on their way to Gloucestershire last night and emergency services helped to distribute three million bottles of drinking water at the rate of 70 a second. Hundreds of shops, restaurants and other businesses have closed because they are unable to offer staff or customers basic toilet and washing facilities.

The Government has ordered power and water companies to make urgent flood risk assessments on key sites to ensure supplies of electricity and water in future incidents. A separate parliamentary inquiry is to investigate the handling of the floods and to see if improvements can be made to contingency plans. The assessments were ordered after it was disclosed that Walham electricity switching station in Gloucestershire – the focus of an operation, involving a 250-strong force of military personnel and fire-fighters, to save power for half a million homes – had been given a recent risk assessment that said it could withstand a flooding incident of an intensity expected once in every 1,000 years.

Most utility sites are assessed on a one in ten-year risk and so ministers and emergency planning chiefs fear that hundreds of key installations could be vulnerable to extreme flooding. This will also be a central focus for the independent review of the flooding incidents that hit the North East and Central England this summer.

Mr Benn and John Hutton, the Business Secretary, have decided that they cannot wait for the outcome of the official review and need information about key sites at high risk of flooding as soon as possible. As The Times reported yesterday, utility companies were asked seven years ago to make their key sites flood-proof or move them to higher ground.

Problems have occurred because electricity substations have been sited on flood plains next to power stations that needed water for cooling. These old stations also used coal, which was often transported to the site by barge.

Similarly, water treatment centres are near rivers because they need to abstract water and top up supplies.

Fola Ogunyoye, a technical adviser to the Chartered Institute of Water and Environmental Management, said the ideal solution would be to move key sites off flood plains or to raise existing structures. Equipment such as electric pumps and sockets could be raised and sites protected by a permanent or temporary flood wall.