FDA describes bottled water as water that’s intended for human consumption and sealed in bottles or other containers with no added ingredients, except that it may contain a safe and suitable antimicrobial agent. (Fluoride may also be added within the limits set by FDA.)

The agency classifies some bottled water by its origin. Here are four of those classifications:

• Artesian well water. This water is collected from a well that taps an aquifer—layers of porous rock, sand, and earth that contain water—which is under pressure from surrounding upper layers of rock or clay. When tapped, the pressure in the aquifer, commonly called artesian pressure, pushes the water above the level of the aquifer, sometimes to the surface. Other means may be used to help bring the water to the surface.
• Mineral water. This water comes from an underground source and contains at least 250 parts per million total dissolved solids. Minerals and trace elements must come from the source of the underground water. They cannot be added later.
• Spring water. Derived from an underground formation from which water flows naturally to the surface, this water must be collected only at the spring or through a borehole that taps the underground formation feeding the spring. If some external force is used to collect the water through a borehole, the water must have the same composition and quality as the water that naturally flows to the surface.
• Well water. This is water from a hole bored or drilled into the ground, which taps into an aquifer.

Bottled water may be used as an ingredient in beverages, such as diluted juices or flavored bottled waters. However, beverages labeled as containing “sparkling water,” “seltzer water,” “soda water,” “tonic water,” or “club soda” aren’t included as bottled water under FDA’s regulations. These beverages are instead considered to be soft drinks.