Chlorine bleach does lose its potency over time--time-related, not event-related (i.e. it doesn't matter if the bottle is unopened). However, here is the mysterious thing--ever see an expiration date on a bottle of household laundry bleach? I've never seen one. I still scratch my head about that. If the manufacturers wanted to sell more bleach, you'd think they'd put an expiration date on it, don't you think?

I agree that bottled water is a big racket. Not all bottled water is just purified municipal water, though. But major brands like Dasani are. Ironically, after reverse osmosis removes all the minerals, certain minerals have to be added back by the bottler to make it palatable and unique tasting from its competitors.