Unlike the tap water, which is regulated by the U. S. Environmental Protection Agency, the bottled water is regulated by the Food and Drug Administration (FDA). Natural Resources Defense Council (NRDC) has compiled a fact sheet on bottled water that addresses a lot of questions.
Bottled water is mostly processed tap-water and may not help you avoid the currently unregulated toxins. You can read a recent report on quality of 173 Bottled Water products by the EWG, here.
There are opposing views on the safety of Bottled Water. You can read the article links referenced here and decide for yourself. In general, bottled water is no safer than the tap water, which is the source for a majority of bottled water sold in the U. S.
The Centers for Disease Control and Prevention (CDC), a division under the U. S. Health and Human Services Department, offers this basic information on bottled water.
Here is the industry view from the the International Bottled Water Association.
Here is a view on the environmental impact of discarded plastic water bottles from the Mother Nature Network.