Why Can't Car Windows Be Opened When Submerged in Water?

[McAliyah]

Because the water pressure is too great. Here are the relevant explanations: 1. Internal and external pressure difference: The cabin contains air, and the pressure difference between inside and outside causes the force exerted by water on the door to reach 150 kilograms, making it impossible to open. When the cabin is completely filled with water, the internal and external pressures balance out, allowing the door to be opened as easily as if in air. 2. Atmospheric pressure: After the car plunges into water 1 meter deep, the door is subjected to the equivalent of 1 ton of water pressure. Inside the car, there is basically only atmospheric pressure, which is negligible compared to the water pressure. Water slowly enters the cabin at a very slow rate. At this point, the driver typically panics and desperately tries to open the door, accelerating oxygen consumption inside the car. By the time the cabin is fully flooded and the pressure on both sides of the door balances out, the driver, having exhausted oxygen and likely ingested a large amount of water, may already be unconscious or lack the strength to open the door.

[DeJudah]

When a car falls into water and the windows won't open, one reason is the immense water pressure. As the car submerges, the external water pressure acts like a solid wall pressing against the windows, making doors and windows immovable. The pressure difference can reach hundreds of kilograms, making it impossible to push open by human strength. Another critical factor is electric windows: once water infiltrates, the circuits short-circuit or overload, rendering the window buttons useless and completely inoperable. Having driven many older and newer cars, I've noticed most modern vehicles use power windows, but these systems fail too quickly when submerged. In emergencies, opening the door or breaking the window is the only way out – use a window breaker or the metal rods from headrests to pry open. Remember, after a car enters water, you only have tens of seconds of golden time – don't waste it struggling with windows, escape quickly. I always keep a window-breaking tool in my garage just in case. The principle of water pressure is simple – it's caused by physical pressure imbalance.

[McPaul]

From an electrical perspective, the main reason car windows can't be opened after submersion is that the circuits are damaged by water. When water enters the vehicle, it causes short circuits in the window motors and control boards, rendering the buttons completely unresponsive. Having worked with car modifications, I know modern windows rely on 12V power supply—water-induced short circuits trigger protective power cuts. The battery also fails underwater, causing system shutdown. Water pressure worsens the situation as it compresses the car body, sealing door and window gaps shut, making them impossible to push open. While windows aren't designed to be fully watertight, water pressure minimizes existing gaps. The remedy is immediate mechanical window breaking—older cars with manual crank windows fare better here. I recommend keeping a portable window breaker in the glove compartment as a lifesaver in such emergencies. Don’t count on opening doors unless internal and external pressures equalize. The deeper the water, the more severe the problem becomes.

[MacJordan]

When a car falls into water and the windows won't open, there are several core reasons. The water pressure difference is too great, with external water pushing against the doors and windows, making them impossible to open. The electric window system shorts out and fails when flooded. I often tell my family, safety comes first: keep a window-breaking tool in the car. The pressure makes opening the door impossible too, with water blocking it. The golden time is very short, so quick action is essential. Prevention is important—avoid driving near water.