What i've always wondered is people bottle water then stick a best before date on it?? uh?? its been in the groud for hundreds of years being filtered through rocks, someone bottles it and put its going to go off on the 23 January 2007. Uh?
Water does go off - if you leave it sitting (not in the fridge) and then smell it , you will notice the difference. I don't know if it's the change in elements it is exposed to, but it definitely does go "off"
Bacteria is trapped in the bottle - it is in the air.
Also the plastic will 'taint' over a period.
But who the heck buys bottled water? Why? It has been proven over and over that tap water is at least as good, often better, than bottled water.
Put it in the fridge and you can't taste the difference.
I saw a programme once on the difference between tap water and bottled water. They said if you empty a bottle of spring water into a jug, put a cloth over the top and leave it in sunlight for several hours, the rays from the sun infuse the water with all manner of goodnessesss and apparently this is the best water you can drink.
Gef, I'm not so sure eyeshades answer is stupid, because animals would rather drink water from pools and ponds that have been exposed to sunlight than drink ordinary tap water.
Just another thought. Are we seeing watercourses drying up because more and more water is being drawn from the ground and bottled before it can emerge as springs and streams?
I'm no geologist but it makes sense to me. You can only get the water out once!