[gwbas1c]

A couple of things:

"Seltzer" and "Sparkling water" often mean the same thing, but a lot of semantics are different. "Seltzer" is usually lower-cost, and often flavored. (IE, plain seltzer is basically sparkling water.)

Some of the seltzers have strong flavors with artificial sweeteners, and thus sometimes the difference between a seltzer and a clear diet soda is very little.

European "sparkling water" (imported here) tends to have less carbonation and is more about the flavor from the minerals.

BTW: I suggest looking at sparkling water from Quebec. About two years ago I took my family there, and we kept buying big glass bottles of something good (can't remember the name) that appeared to be local. It'll be more like San Pellegrino / Perrier, compared to an American seltzer with heavy flavoring.