>>I'm still looking for the definitive answer re untreated tap water storage life. If anyone can give an answer I'd be interested. Still, if you were desperate for a drink, how bad could your stored water get ...<<

I found the information on this subject frustratingly incomplete, full of nonsense like "bacteria count" without saying what KIND of bacteria were found (as though it didn't matter)- and, in the end, I decided to go my own route.

I don't treat the water in storage. I've rotated the stock every 2-3 years at best. I have multiple ways of treating it- three Katadyn filters in different sizes, stored chlorine bleach, several ways to boil, Potable Aqua tablets.. heck, I've got enough fuel stored I could probably distill it- WHEN and IF it's ever needed for drinking. Chances are it will never be used that way- last time we had a drought, I rotated part of it out by using it to water the garden (which I think almost got me turned in to the "drought police" by a busybody neighbor, who didn't know, and probably wouldn't care that I didn't replace the water I used until after the drought was over). In a known short-term emergency, we might be using it to flush toilets.

I don't see the point in treating it for years before it's needed, especially by constantly adding more and more toxic chemicals.

Yeah, Ive seen a little slimy algae near the tops of the barrels- that's a far cry from coliform bacteria or even Giardia. Probably wouldn't hurt me to drink it untreated anyway (I have 1,000 coffee filters stored that will take care of the algae as a first step), but it's a moot point- I don't intend to. I'll treat what's needed for drinking when it's needed for drinking.