You just draw good shit

Original kind of superhero here =3=3=3

Yeah, she can't create water or pull it out of the air (presumably) but oh, can she manipulate what's there!

You actually pretty much nailed everything that was in the commission description about her powers right there ^^
...Aside from a certain other power that the commissioner was kind enough not to ask me to draw, her ability to store the water inside her in large quantities... yeah XD

Well she can't create water out of nothing (that's team member #4's job) But she can pull it out of the air pending there is enough moisture in the air around her. Also as StarFighter has already mentioned before, she does have that ability to blow herself up huge with water or perform a ability called "Liquid Muscle" where she absorbs the aforementioned fluids into her muscles making her huge and buff and giving her muscles the power the same as you would find in a hydraulic ram (except without oil though she can infuse that in too)

Also yeah she can manipulate what is there including gases, plasma and fire considering they are themselves "fluids".