I learned about this in one of my haz mat recert classes. The plastic bottles we buy that contain everything from water to pop that we consume leach plastics into their contents over a period of time. That is why bottles have an expiration date. Water does not "go bad" if it is stored in sealed glass or metal containers. As for myself I use filtered water. Not that I'm fearful of some local contamination (we have some of the best water in the nation) but because water is treated with chlorine and that is a known carcinogin.
A toast to your health