We had to drive through several places with water covering the roads during Harvey last year - and, perhaps we were lucky, didn't have any problems.
Though, we were pretty conservative about it - raising the air suspension to very high, verifying the water depth by observing other vehicles, and then driving slowly on the path that seemed to have the least depth of water.
We've since purchased a Model X - which rides higher off the road, and if this happens again, we'll plan to drive the X instead of the S (which sits much lower).