Water damage does not stop when the flood recedes. Corrosion in the wiring and sensors can take months to surface, and a surprising number of flooded cars quietly reappear on the used market with clean-looking titles. Beyond the essential first steps of disconnecting the battery and never starting the engine, there is a bigger risk buyers need to understand. Here is what actually happens to a car after it floods, and how to avoid buying someone else’s flood car later.