I have some 6-packs of 500 ml or 710 ml bottled water in the car. The 6-packs hold together instead of having loose bottles all over. I've found that after a while they cave in slightly, i.e. they heat up and air gets forced out of them, and then when they cool down again, the resulting internal vacuum collapses them slightly. But I found that even after a couple years, they still taste fine. I used to reserve them for emergencies and semi-emergencies but now I just drink them when I feel like it, replenishing frequently enough to always have a supply on hand in case something happens. That ongoing consumption and replenishment (a few bottles a month or so, more if I go on a trip) eliminates the need for planned rotations or pouring out water.

I've had poor luck with larger containers than those small bottles. That expansion and vacuum effect means that the bigger bottles always leak. I also figure the bottled water in the retail 6-packs is more sterile than putting tap water into some funky old bottle.

If I were really dedicated I suppose I'd get those foil pouches or aqua blox, but those things are ridiculously expensive compared to the 6-packs.