How can you tell if a car has been damaged by water?
A few ways:
Test Drive it first- Thoroughly examine the vehicle by listening and feeling it operate. Try the highway, hillsides and in the city.
Check the gauges- Are they all working? Electrical systems have become an integral part of the modern vehicle. Test the windows, lights signals, and blow the horn.
Do a complete visual check- look underneath for any signs of a fram change, new parts or panels or rust. Water will rust metal.
If you're not sure, Check with your mechanic!
You can also go to the DMV and get the history of where the car has been registered and when. That would be a good indicator if a car was sold around the time of the damage.