I hate to sound like a dissenting voice here, but as universal as bottled water has become, why not just add a liter bottle to your EDC, that way, you've already got water on stand-by, and a lot more durable, sealable, carryable, fillable container when you need it. There shouldn't be a problem with anybody looking at you strangely for carrying one, eccept for the occasionable person who snickers quietly about your paying so much for bottled water. This brings to mind a story about how bottled water got started... a bunch of French businessmen were sitting around the board room one day, and suddenly one of them said "You want to know just how gullible I think the American public really is..."
After that... just something to think about, spell Evian backwards.

Troy

P.S. No offence meant to our French friends, sometimes it's good to poke a little fun at yourself, and somebody had to be the villain.