What height should bead board be installed in bathroom?

http://homeguides.sfgate.com/standard-height-wainscoting-bathroom-89841.html

Bead board used to be installed at the height of the tallest chair used in the room - it was to protect walls. For a bathroom, just make it the most pleasing height. Perhaps take the height from the height of the vanity?

This is a pretty good guide

http://homeguides.sfgate.com/traditional-height-beadboard-90056.html

I think this is a matter of taste. But I think average is 30-36", if you intend to do a chair rail.

We put ours at the height of the vanity plus the tile back splash. This included the moulding that we added at the top of the bead board. It is not a "standard" height because we built our vanity taller than the traditional vanity height.

I've seen them put at all different heights. However, for the best look, I'd put it at a height that works with your vanity. If you want a backsplash look go a bit higher, if not you can make it even with the back of the unit.

Waist height otherwise it could crowd you in.