Are water spirit users ever seen? In Kaze no Stigma, fire, earth, and air spirit users are clearly seen using their abilities. Ayano is a fire-user, Kazuma is an air-user, and the Tsuwabuki family are earth users. Water users are never even shown.

Are they ever mentioned as existing, and is there any reason given, even in-universe or by an author, for them to never be shown?
Since the writer is dead, the story won't continue on from the point where it prematurely ended, but I think it's very likely that the arcs that would've followed (chasing down Rhodes and Lapis/Tsui-Ling) the ending would feature Water mages sooner or later, otherwise mentioning it to begin with would've been pointless.