The U.S. Food and Drug Administration and States regulate bottled water. For general information about bottled water, some sources are the International Bottled Water Association and NSF International.
The The U.S. Environmental Protection Agency (EPA) provides the following information on bottled water and tap water:
Bottled water is not necessarily safer than your tap water. EPA sets standards for tap water provided by public water systems; the Food and Drug Administration sets bottled water standards based on EPA's tap water standards. Bottled water and tap water are both safe to drink if they meet these standards, although people with severely compromised immune systems and children may have special needs. Some bottled water is treated more than tap water, while some is treated less or not treated at all. Bottled water costs much more than tap water on a per gallon basis. Bottled water is valuable in emergency situations (such as floods and earthquakes), and high quality bottled water may be a desirable option for people with weakened immune systems. Consumers who choose to purchase bottled water should carefully read its label to understand what they are buying, whether it is a better taste, or a certain method of treatment. For more information, download the U.S. Environmental Protection Agency booklet: Bottled Water Basics PDF (2MB PDF). (Source: http://www.epa.gov/ogwdw/faq/faq.html)