We really have no idea what sonic shower is or how it works. For all we know, showers in the future have the option of adding sonication, just like showers today have the option of adding hot water; few people would choose to ignore the hot water setting now that it has become available, and virtually nobody would choose to disconnect his shower from the hot water system even if preferring cold showers. But even a sonic shower would be a water-based device fundamentally. Or some other suitable solvent, at any rate.
The one "unrealistic" aspect here would be people calling their showers "sonic showers" when nobody in his right mind would call his shower "hot water shower" let alone "tapwater shower" today. The extra word is unnecessary and uncommon usage.
But who does
call the device "sonic shower"? It's a DS9/VOY thing exclusively. Perhaps Terok Nor did not have a sonication option installed originally, so showers with this otherwise commonplace feature retrofitted by Starfleet are specifically savored. Ditto for the shot-to-hell Voyager
which might have suffered loss of sonication systems, forcing most people to subsist on old-fashioned water-only showers, and Torres (the only one to use the term, really) would be rubbing it in that being a skilled engineer carries fringe benefits.
The one TNG exception is "The Game", where Starfleet Academy at Earth is credited with sonic showers - and they can be programmed to spew mud! Also, we know from "Body and Soul" that sonic showers come in hot and cold varieties.