[steve86]

Sure, that’ll supply enough water for 3 or 4 gerbils. Just kidding, I keep one on my motorcycle to use streamside. But you need to be able to disinfect also.

[RC one]

I have had it for years "just in case" but I have never had to use it. Occasionally I will filter some tap water just to make sure it works. I probably ought to become more familiar with its use than I am.

In a flood situation, I would be worried about chemicals in the water as much as microbes. I would think the best solution would be some kind of a solar still but even that might not remove all chemicals. In a true survival situation, I would look to scrounge for sealed beverages as I removed myself from the contaminated waters and use my filter only if I had to and even then, I would be looking to filter relatively clean water if possible.