Oh, I see. lol, well, it's kinda funny in retrospect. I'm obviously easily confused <img src="/ubbthreads/images/graemlins/smile.gif" alt="" />

I think water can start to grow bacteria once the seal breaks down in the plastic. Even though plastic will be around for Milennia, after we're gone, before it fully breaks down, the seals degrade quickly enough to enough sludge to slip in. Chances are it's still good for at least a couple years after the exp date, but be sure and smell it before you drink it. if it smells rancid or stagnant, it probably is.