Do you mean distilled water? Not necessarily. Bottled water isn't always distilled, it may just be filtered in some way. It should be clearly labeled at the store.
FYI, water can be:
"tap": what comes straight out of your house tap and the contents will depend on whether you get water from a municipality source or your own well.
filtered: this can mean any number of things but isn't distilled. Could be filtered just to remove sediment, sulphur, specific minerals, organics, etc.
RO filtered: water that's run through a reverse osmosis filter. Most (but not every single bit) of minerals are removed, also microrganisms and chemicals are removed.
spring: what's in it or where it's from totally depends on the claims of the supplier. Could even be someone's tap water.
de-mineralized: supposedly has all mineral content removed.
distilled: supposedly "pure" H20 because it is re-condensed steam.