If you want to start the car in flooded areas after the water has dropped, you should note the following ADAC tips:
In no case turn on the ignition and move the vehicle! Because if the water could reach the air intake duct, there could be a major engine damage (water hammer). It is best to first contact affected persons with their insurance. This must give an assessment of how to proceed with the vehicle. That's the only way to play it safe!
Important: Take a photo of the damaged vehicle.
If you need to get your car out of the water, you should pull it out with a tow rope and leave it in a dry place. Important: disconnect the battery to prevent short circuits. Then the car should be brought to a specialist with a van, because it is not sure if the brakes work.
If the car was completely submerged, the damage is often so high that repairing the vehicle is too time-consuming. However, if the water has risen only to the bumper and the interior remained dry, the risk of major damage is rather low. Important: Anyone who has taken out a partial comprehensive insurance for their car can handle damage through the insurance. But this is only possible if the water has come to the car - and not vice versa.
Source: ADAC Press Source: Rich Moffitt