It's not really a big deal.

When I was doing a lot of mountain biking I used to hang my muddy bikes by the saddle and clean them with a hose and sponge. I still do that once in a while, especially the ones that I ride on the limestone katy trail. I've never had a lick of trouble with rust or washing the grease out of my bearings.

I live in the midwest and have an indoor, low humidity space for bike storage. YMMV.