A few years back, we lived in an apt complex. Someone tried to drive a too tall moving van into the parking garage and tore a bunch of plumbing pipes up (they actually wedge the rented van in the garage and abandoned the van with water and sewage running off of it and their dog shut in the back).
We were chatting with some folks that lived in a house behind the complex, and they said that they generally keep a bunch of old plastic gallon water jugs full of tap water stored, that they rotate through so that if something happens, they have a bunch of bottled tap water on hand. I thought that was pretty cool and not something that I'd ever done or heard of.
Since moving into a house, in the country, we've been working on that. We've got a second fridge in the garage/out-building. Neither of us likes the idea of water stored in plastic long term for consumption. But we get this stuff from time to time (the grandsons love it, it's got to be better than soda).
It comes in 1.5L glass bottles. We wash the bottles thoroughly. We have a water distiller and distill water that we store in them. Then we're keep them in the spare fridge which I believe will also work as a heat sync to help the fridge stay cooler if the power goes out. Storing tap water, even filtered through a filter (like a Brita or something similar), in glass bottles, eventually the inside of the bottle gets nasty. But the distilled water seems to stay clean. I do occasionally use the water and wash the bottles again. They never feel nasty, but I figure it can't hurt.
So we have quite a bit of distilled water stored in glass containers that should last a long time without being an issue.