Looking back on Mojang's plans for the "Realism Mode" what with having to eat and drink every Minecraft week and three days, respectively, I was think that, say if you're held up in a desert without any water around (spawned a few too many times there) and we all know that the air contains the blessed fluid, that perhaps there could be a machine in which you would put a single bucket in the upper slot and a battery in the lower and after a minute or so, it would fill the bucket with water fresh to drink. It would work something like the canning machine, if you will.
Unfortunately, the recipe I had in mind escaped me, so I will edit this (if possible) with a recipe I think would be balanced.