The many different kinds of bottled water on grocery shelves can be hard to sort out. Here’s what the labeling means:
Spring water: About 75 percent of bottled water in the U.S., this is water that flows naturally from underground. It’s supposed to be protected from pollution.
Sparkling water: Spring water that contains carbon dioxide gas.
Mineral water: Spring water that naturally contains 250 mg or more of dissolved minerals (like magnesium and calcium) per liter.
Drinking water: Bottled tap water from a city water system. If it’s been filtered or disinfected first, the label doesn’t have to tell you which municipality it comes from.
Purified water: Distilled or otherwise treated/filtered water (i.e., ion-exchange, reverse osmosis).
Distilled water: The steam of boiled municipal (city) water.
Boiling gets rid of some contaminants, but not all -- benzene and chlorine, for example (but some companies filter these out separately).
Source: Center for Science in the Public Interest (http://www.cspinet.org/)