|The following is based on Fallout: New Vegas cut content and has not been confirmed by canon sources.|
There is no in-game model for the water, but the G.E.C.K. editor does contain an inventory icon and a message icon. It is unknown what weapon would have used this, but it is marked as "playable", hinting the Courier could use it.
PC Pure Water can only be obtained with the use of console commands.
Pure Water was to appear in Fallout: New Vegas, but was cut from the final release of the game for unknown reasons.