As long as the amount of water utillized is not too great then this idea makes a lot of sense. Some sort of recycling and heat exchange may well be needed in concert.. Anything which adds to unfuelled weight is detrimental for a Space vehicle and so if such a system could be employed it could both lower operating temperatures and reduce the need for high-cost materials as a result; as well as hopefully reducing weight accordingly. Assuming one isn't utilllizing Titanium from the start.
All bureaucrats(oh, and politicians!) MUST die!