[MrWookie]

This is somewhat true, but it's not the whole picture. It's true that water does contain dissolved gasses, and these gasses affect the flavor. Have you ever drunk boiled water, say, while out camping or something? It tastes pretty bad, having lost almost all dissolved gasses. Bottled water, though, is going to be pretty close to equilibrium when it's bottled (if there was much of an exess of dissolved gasses, we'd call it carbonated water), so there's not much outgassing that can occur UNLESS it warms up. An open bottle of water in your fridge won't outgas hardly at all, but if it warms up to room temperature, its capacity for holding dissolved gasses diminishes, and it'll lose some.