That is one of the perils of using water as an element in D&D. However, water can also be a good medium for delivering other status effects and attacks, such as poison, disease (bog water... ugh), slow effects, nausea (bog water, again), suffocation, etc. It comes in several forms, from liquid water to solid ice to nearly-gaseous steam/mist. It can be versatile, but then again it certainly works well enough as a companion or foil to the pyromancer.