An on-site water bottling operation at Holyrood is being planned by Scottish Parliament bosses.
Parliament chiefs said bottle use was relatively low
MSPs were told that up to 600 bottles of mineral water are consumed every week during Holyrood business.
Concerns over the environmental impact have led to a new service being considered which would see filtered tap water bottled at the building.
Green MSP Robin Harper suggested that politicians and staff would be better served from jugs of tap water.
Alex Johnstone, speaking for Holyrood's corporate body, described bottled water usage as a "relatively small total", and pointed out that used bottles were recycled.
But the Tory MSP recognised the environmental concerns, saying: "We are investigating the possibility of bottling filtered tap water on site."
He added: "Hopefully this will come to fruition in the not too distant future."
Mr Harper said: "It is incredibly unenvironmental to serve what is essentially plain water in bottles, whether they're recycled or not."
"This is a totally unnecessary impact on the environment when you can take water out of the tap.
"I do not see why is it not possible for jugs of tap water and glasses can be provided, at least in committee rooms."
In an attempt to broaden the debate, independent MSP Margo MacDonald said that on the subject of "excessive water" around parliament, it was time to get rid of the three small ponds outside the building.
Mr Johnstone said he was unprepared to answer pond-related questions, but added: "I can give the chamber a guarantee that we will not consider using that water to fill the previously mentioned bottles."