I've been doing the same -- have a few one gallon spring water jugs stashed, along with a few flats of the 0.5L bottles.

I tried storing tap water but that just got to be a pain in the butt. Especially trying to rotate it, etc.

Found that the 0.5L bottles work great, plus I drink more water. (A good side benefit.) <img src="/images/graemlins/grin.gif" alt="" />