In our 72 hour bags, I have some water in USCG approved water ration bags, like this:



I believe we have 12 packages in each kit, not a lot, but, it's the "break glass" reserve if the rest of the water runs out. It has a 5 year shelf life.

I also carry 3 1L Lexan Nalgene water bottles, and a Katadyn Guide model filter. I have a package of 30 Katadyn MicroPur MP1 tables in the kits also. Those are all actually in the backpack. In the back of both vehicles, which is where the backpacks sit, is a case of spring waters, 24 16-20oz bottles, depending on what's on sale. We go thru a lot of this stuff, so the case in the back of the cars is rotated frequently, so it's always "fresh".

If we were bugging out from home, we'd augment what's in the car with a couple of 5 gallon water jugs that we use camping.