I've been doing this for a long time, no problems at all I dry them quickly by powering them up after I wash them and shake off the water on it as much as possible.
WOW! You are daring!! LOL!!! I dare not start anything up after washing, not until I have totally roasted it in the sun!
Oh, I don't think the grease in the bearings would be affected by the water. In fact, the grease should keep the water out. I'm more worried about short-circuits if I power the fan up after wetting it.