Unlike a fender-bender, water damage is insidious. It doesn't always show up on day one.
If water entered the engine (hydro-locking) or the transmission, the internal components are likely compromised. Even differential fluids can be contaminated, leading to premature gear failure. should i buy a flood damaged car
Are you looking at a right now, or are you just starting your car search ? Unlike a fender-bender, water damage is insidious