Nice info, Tom, although it just goes to show the wisdom of "not putting all your eggs in one basket." Even these carefully manufactured water supplies ended up contaminated from a failure along the way. Regardless of whether it's a compromised seal, tiny crack, burst container from freezing or whatever, it's good to have more than one water container in case Murphy comes knocking.

Theoretically, clean water in a clean, inert container should stay that way indefinitely. But that's in a perfect world, as this lifeboat supply example shows. If someone wants/needs self-stored water to keep for a long, long time without changing it out, then maybe they just need to accept the inconvenience of assuming that it needs purifying in the event that they ever need to drink it.