Is it possible for an unopened bottle of purified water such as Aquafina or Dasani to go stagnant?

Actually, I've seen a bad bottle of Aquafina. A case, actually. It was 4 years out of date, and stored right by a skylight. It had a definite chemical scum on the top of the water in the bottles. However, in most cases, the answer is no.

Spring water, by the way, is no better for you than any other bottled water. All "spring water" means is that the water came from an underground formation and flowed naturally to the surface. There was a case sited where the "spring water" came from a plant in MA...about 400 yards from a Superfund site. Or the "Artesian" well in southern california located about a half mile from a municipal well closed due to mercury contamination. Those tags, "Artesian", "Spring", or "Purified" come from the FDA's "standards of identity". That's not to say that most bottlers don't test their product extensively (Aquafina and Dasani are both tested extensively being Pepsi and Coke products respectively), but the guidelines that the FDA sets for bottled water are far less strict than what the EPA sets for tap water in the US.

Of course, you're probably safe no matter what. A vast majority of bottled water (including "Spring" or "Artesian" water) comes from nice safe municipal supplies...aka, tap water.

For the most part I do not like Aquafina water I go to Walmart and get there brand of water or Sam's choice Aquqfina water has a harsh taste I think if right out of the case unless it is refregerated

but make you think what is going on in that water!

It's relativity. For example, the best pisses I ever take is when I had to hold it in for a long time and then finally got a chance to go. It's great! But do I want ALL of my pisses to be like that? Hell no! The only reason it feels good is because my body was pushed to the limit and was given relief only after an extended period of time. Similarly, with the 3AM bathroom water, you're body is so uncomfortably thirsty that you actually wake up to hydrate yourself. The wonderful feeling that you have associated with 3AM bathroom water has more to do with relief, and not so much with taste. If you drank 3AM bathroom water all of the time you would see how inferior the taste is compared to bottled or filtered water.

Yes. I once went to a small convenient store and got a bottle of Ozark and it was real bad. It didnt really smell but the taste was unbearable. There is an expiration date on water so check that just like you do other food. I have water right now that says its good till 2008 so it does keep for along time though.

WAter does not have an expiration date. It's water. If it's been properly filtered, there's nothing in it to go bad.

It doesn't go stagnant--it IS stagnant (still, motionless, quiet, stationary). And, it won't go bad. Expiration dates are there to prompt you to use the water (or stupidly throw it out) and buy more. Period. Ask any chemist.

It's better to get spring water than purified water. Purified water is nothing more than tap water. Tap water is purified at the water treatment plant, where chemicals are added to kill any mildly toxic germs.

Most people who work at water treatment plants will tell you that the tap water is good. It is--when it leaves the plant. Tap water is only as good as the lines that carry it to your house. The chemical they add make the water taste bad, but in the U.S., it's generally safe to drink.

Yes, they do actually have an expiration date. Plus you run the risk of it being contaminated by a small break in the bottle.

After many years, yes.

yes but it takes a while