The New York Times gets it right today; in an article about how people drink more bottled water and less of just about everything else, they claim that
As I said before, NYC water rates recently went up to 0.27 cents per gallon; assuming that "eight glasses" means "eight [measuring] cups", or half a gallon, this is correct. They then go on to point out that buying bottled water at the same rate would cost about $1,400 yearly. If you work it out, that's $4 a day, which values a 16-ounce bottle of bottled water at $1; that seems about right if you buy them individually, not in cases.
THOSE eight daily glasses of water you’re supposed to drink for good health? They will cost you $0.00135 — about 49 cents a year — if you take it from a New York City tap.
But with bottled water, you're really paying for the bottle, not the water.
On a related note, the Philadelphia Water Department is now giving out free bottles of tap water for events. The thinking is not financial, but environmental; they figure that if people are aware that tap water tastes good, then they won't use as much bottled water in the future. Bottled water is bad for the environment, because it's packaged in plastic containers and is often transported very long distances. Yesterday I saw someone buying FIJI water at the store on my corner. This comes from -- you guessed it -- Fiji, which is eight thousand miles away.
Personally, I buy bottled water for the convenience when I'm away from home but would never consider buying bottled water for my home. I've also been known to refill empty bottles with tap water, although there are rumors that that's unsafe.