According to the Aquafina official site www.aquafina.com, they use the patented state of the art hyDRO-7 system to purify there water to give us the pure and perfect taste in their bottled water. According to their site what the hyDRO-7 system does is remove anything that make the water taste bad. Personally I think this whole notion of bottled water is ridiculous. To pay so much for a barely detectable taste and brand name for the same water we are provided with at home is a moral travesty. Buying what I call re bottled water from corporations is all we are doing. Its just short of selling ice to a Eskimo, we are like the Eskimo who can't see that he is surrounded by the very ice we just bought. Maybe its just a general mistrust of the corporations, who's only goals are to make more profit than what they spend or maybe its a valid argument to be concerned with. One thing I will say is that bottled water is convenient.