What Is Soda Water, Really?

Soda water, club soda, seltzer, sparkling water, tonic water—what's the difference? Is there even one, or are all of these different terms for generally the same thing? We happen to be in a golden age for water with bubbles. It seems like every day, a new brand emerges boasting a different range of flavors, with different health benefits and natural ingredients all upping the ante on that refreshing burst of fizz so many of us can't get enough of. That's not even counting the simultaneous rise of hard seltzers, taking this trend into adult-beverage territory. So, it feels more important than ever to actually understand what we mean when we say "soda water." If we ask for it at a restaurant, for example, are we actually going to get what we have in mind?

Luckily, Slate broke down the taxonomy of water that sparkles. It turns out, this is its own little world of H2O with some bite! According to the article, "carbonated water," "sparkling water," "bubbly water," and "fizzy water" are, yes, all the same thing. They all refer simply to water that is carbonated, either naturally, as can happen in some mineral springs, or with carbon dioxide tanks. From there, we have to further break things down to catch certain similarities and differences that may seem subtle but could actually determine why you like one bubbly water over another.

Soda water has the longest historical roots, according to Slate. When artificially carbonated water first hit the market in the late 18th century, it was called "soda water." The site writes that you could call soda water "seltzer." Both are, simply, water with carbon dioxide. As Eater points out, the absolute plainness of seltzer is what makes it such a perfect canvas for so many brands to add flavors and/or alcohol. 

The important distinction between "seltzer" and "sparkling water" is where the bubbles come from. Artificially carbonated water is "seltzer," explains My Recipes. Meanwhile, brands like La Croix are "sparkling water," says People. Sparkling water's carbonation is natural. The FDA regulates seltzer as a "soft drink" and sparkling water as "bottled water." One more wrinkle is that "mineral water" can be either flat or sparkling, as long as it comes from a mineral spring. Perrier and San Pellegrino, writes People, "are sparkling mineral waters."

"Club soda" has extra ingredients. It's artificially carbonated water with added sodium and/or potassium salts, meant to neutralize acidity and actually taste more natural. Finally, tonic water isn't water! It's a sweetened soft drink with carbonated water. So, soda water is basically seltzer and falls under the carbonated-slash-bubbly water umbrella; but minor tweaks make it different enough from sparkling water, club soda, and tonic water that it pays to know the distinctions when you're shopping or ordering.