Water

[cbs]

remember also you can boil the water in a pinch.

[theGinsue]

Thanks for the response Jerry!

cbs - Of course boiling water does help cleanes out a lot of contaminants, particularly of the bug type. The problem with boiling is that it does nothing for removing chemicals, hard metals, etc. that may be in the water. To remove those types of things you'll need a good filtration system.