I very rarely buy bottled water. Practically never. The environmental impact of producing and shipping water is ridiculous.
* Just on the matter of price, a gallon of bottled water can cost 10,000 times more than a gallon of tap water.
* Perhaps you've seen the Brita commercial which states that the number of plastic water bottles consumed in the United States each year could circle the Earth 9 times. That is insanity. Every one of those bottles has to be manufactured, and even if it is made from recycled materials, there is a carbon footprint to creating them.
* Then there is the transportation. For some reason, people have been lead to believe that they will be healthier if they drink bottled water from some far off locale where the water is "purer". But that means shipping full bottles of water thousands of miles.
* And finally there is the question of whether bottled water is even healthier for you. The EPA's standards for tap water are more stringent that the FDA's are for bottled water. That's right. You're more likely to be drinking safer water if it is from the tap.

Here is a great article I found laying out precisely the carbon footprint of 1 liter of Fiji water. Here is a quick synopsis of the costs of Fiji water:
In summary, the manufacture and transport of that one kilogram bottle of Fiji water consumed 26.88 kilograms of water (7.1 gallons) .849 Kilograms of fossil fuel (one litre or .26 gal) and emitted 562 grams of Greenhouse Gases (1.2 pounds).

It takes 7 gallons of water for you to get 1 liter of bottled Fiji water. What an unconscionable waste.

Personally I've had a sink top or faucet water filtration system in my home for at least a decade. At the gym, I keep a refillable bottle of water and use the water fountains, which are almost always filtered. Heck, I even drink from the water fountains of playgrounds when I'm playing tennis. Me & bottled water aren't friends. You shouldn't be friends with bottled water either.