I read on Dr. Wilson's site that spring water is fine that you buy at the store in plastic containers. I have been buying big gallons from Whole Foods of the spring water following Dr. Wilson's recommendations. I know he had mentioned something about the reverse osmosis water not being so great, but don't remember specifics. Here is the link: http://www.drlwilson.com/ARTICLES/WATER.htm
I always thought that the plastic wasn't good for your body and can cause breast cancer, so I was baffled by the okay of this by Dr. Wilson, but just decided to follow it anyways because I didn't know of any other protocol that was better at the time.