Inspired by this recently resurrected question and beginning a re-watch of ST:Voyager.
Janeway's stateroom has a tub.
Whereas the average crew quarters seem to only have a sonic shower.
Yes, there are!
In the first episode of Voyager (the Caretaker), Tuvok walks in on Neelix taking a bath. This happens in guest quarters (not a holodeck), so regular crew quarters may not have bathtubs.
Yes, Neexlix aand Capt. Janeway use a bath, Torres has a sonic shower on more than one occasion.
Neelix also mentions the fact that voyager has latrines, as some were broken... but I can't find specific reference to the episode. The only written source i've found is :- http://star-trek.answers.wikia.com/wiki/Why_does_it_seem_that_there_are_no_bathrooms_on_Star_Trek
I think the episode is Year of Hell.