The pledges formed the centre-piece of a "fightback" by nine of the 10 water companies against the wave of adverse publicity since privatisation seven years ago.
Denying that the campaign was motivated by a fear of Labour's windfall tax, the nine publicly committed themselves to "never again" subjecting their 50 million customers to rota cuts or standpipes in the street.
Other pledges included an end to the discharge of untreated sewage into rivers and the sea, improved compensation schemes for customers and a drive to reduce leakage rates.
However, the campaign backfired almost immediately after the companies were unable to give firm dates for when hosepipe bans would become a thing of the past or detail how efficiency gains would be divided between customers and shareholders.
Frank Dobson, Labour's environment spokesman, said the pledges fell "far short of what the next Labour government will require them to do" and re-iterated the party's intention of imposing a windfall tax on the privatised utilities.
The Government's Environment Agency, meanwhile, said the water industry's record on pollution since privatisation had not been good, adding that it wanted to see more detail of how it planned to turn "its vision into reality" and the time-scales involved.
Consumer watchdogs also voiced scepticism. Elizabeth Monck, chairwoman of the Thames customer services committee of Ofwat, criticised the absence of any detailed breakdown of how excess profits would be shared between customers and shareholders: "Substantial profits have been made since privatisation and customers are looking for a much clearer message about where the benefits are coming to them."
John Green, managing director of Anglian Water and chairman of the Water Services Association, which is co-ordinating the initiative, insisted the pledges went well beyond the statutory requirements contained in the water companies' licences. He was unable to give an commitment, however, that the pledges would stand if Labour got in and levied its windfall tax.
The nine companies backing the initiative are Anglian, North West Water, Welsh Water, Northumbrian, Severn Trent, Southern Water, South West Water, Thames and Yorkshire.
However, only four of these - Northumbrian, Severn Trent, North West and Welsh - were able to pledge publicly yesterday that they would never again enforce hosepipe bans. Their commitment to end discharges of untreated sewage was equally patchy, with some companies refusing to give a time- scale.
Brian Duckworth, managing director of Severn Trent, said: "The water industry has come in for a lot of criticism and we believe that some of this is justified. Some things have gone wrong but far more is going right for the industry."
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