Where I live there's no problem with the tap water at all. Not foul tasting, nor full of impurities, so I see no reason to avoid it in favour of the bottled variety. In fact, it tastes good!
So I often wonder how come there's been such a boom in the sale of bottled water. Some folk even preferring the imported variety! I've also wondered if bottled water is something of a fad ... I really don't know.
I see every good reason, when travelling in places with impure water supply, like say, India or Indonesia, to resort to bottled water. But in Melbourne, Oz? No ... no need. So how come everyone seems to be doing it?