The terms carbonated, sparkling, soda and seltzer water often get used interchangeably, but they're not precisely the same. They are all clear waters with effervescence, but the mineral content varies, and the bubbles may occur naturally or be added with carbon dioxide.
Sparkling water generally has no additives, although some companies do produce flavored varieties. Naturally sparkling water comes from mineral springs. The Food and Drug Administration describes mineral water as "water containing not less than 250 ppm total dissolved solids that originates from a geologically and physically protected underground water source." Naturally occurring gases may produce bubbles in sparkling mineral water, but carbon dioxide can be added.
This broad category includes sparkling water but also club soda and soda water, which are interchangeable terms. Soda water differs from sparkling water due to the addition of salt and/or baking soda to balance out the acidity created by carbon dioxide. The leveled pH of soda water as compared with acidic sparkling water produces a lighter taste better for mixing with flavors or in cocktails, while the more distinct flavor found especially in naturally sparkling water is typically enjoyed on its own.