Guests and MPs are served mineral water at committee meetings
The House of Commons is to continue to serve bottled water in its meeting rooms, despite pressure across Whitehall to switch to tap water.
A cross-party MPs committee decided at a private meeting on 1 April to keep using mineral water from Hampshire.
Labour MP John Spellar said it was "disappointing" MPs were not prepared to take "simple steps" to cut waste.
Committee chairman Frank Doran said the decision was taken on cost and hygiene grounds but may be reviewed in future.
More than 30,000 litres of mineral water are served up in Commons rooms each year.
The water is sourced from Broughton, Hampshire - 77 miles from Westminster - and it is estimated that the company delivering it has clocked up more than 70,000 miles over the last five years.
The issue has recently been re-examined by the Commons' facilities department, amid growing concerns about the environmental impact of bottled water.
Last month Civil Service chief Sir Gus O'Donnell wrote to the heads of all government departments suggesting they stop serving bottled water at meetings.
But the Commons administration committee has decided to stick with it.
Former minister Mr Spellar said there was a "considerable" impact on the environment - from transporting it to burying the packaging in landfill.
"I find it disappointing and extraordinary that MPs, who are constantly lecturing the public on cutting carbon footprints and helping the environment, are not prepared to take simple steps themselves."
Jeanette Longfield from the lobby group Sustain, which campaigns against bottled water, said the decision made MPs "look like fools".
"When the whole of the rest of government has been instructed by the Cabinet Office not to waste taxpayers' money on bottled water, who the hell do MPs think they are to carry on?"
But administration committee chairman Mr Doran said: "The committee looked at all the options for providing water in committee rooms and decided on the grounds of cost and hygiene that there was no better solution than the one in use at the moment.
"However, this is something the committee could look at again in future."
The government says evidence suggests that drinking tap water uses about 300 times less energy than drinking bottled water.
The House of Lords is considering installing an on-site machine to bottle its tap water for meetings, having previously resisted using jugs of tap water because of concerns about hygiene and time constraints.
Whitehall is also phasing out its use of plastic bags as part of a wider programme of environmental action.