Purified water

Purified water is (as the name suggest) water that is completely free of radiation and so it can be safely drank without harming the player. In addition it also heals for a lot more then Dirty Water does by awarding +20 health instead of +5 (from dirty water). It isnt found that often in the world but can be requested by the butler robot that takes care of the players house in Megaton/Tenpenny Towers (depending on players choice of quests).