What Happens When a Car is Submerged in Water

What Happens When a Car is Submerged in Water

Your car has several features that help it withstand water to a certain extent, like the exterior paint that prevents the underlying metal from oxidizing and rusting, or your rubber-backed carpets that keep water from reaching the metal floor of your vehicle.

However, floodwater is a completely different game altogether; it will infiltrate your car from all directions and gradually compromise the interior components, including your engine.

If you are wondering if you can restore a flood-damaged vehicle, read on to find out what happens when a car is submerged in water.

What Are The Different Types Of Water That Can Flood Your Car?

The level of damage your car sustains when submerged in water will generally depend on the type of water:

a) Freshwater flooding

Your car is pretty resilient to freshwater. Usually, the car can be repaired and restored to its original state if it was only submerged up to the dashboard, as long as the water was not heavily contaminated by pollution or silt.

You just have to dry it out thoroughly, clean it, and then repair any damaged systems. However, if the water level goes up past the dash, it can cause too many expensive electrical faults and you may ultimately have to write it off.

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b) Seawater damage

If you live near the coast, this is the type of water damage you are more likely to encounter. Seawater is a much more dangerous adversary than freshwater. Salty water quickly penetrates deep into your vehicle and accelerates corrosion.

If your car is only submerged up to the door sills, you can probably clean it up and return it to the road.

However, if the water reaches the dash, seats, and other interior components, the resultant damage will total your vehicle.

The cost of doing the repairs can be expensive (sometimes exceeding the total value of the car), so it’s not really worth the trouble unless the car holds some sentimental value.

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Flood-Damaged Cars: What Happens When A Car Is Submerged In Water?

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Here is what you can expect if your car is submerged in water:

1. Electrical malfunctions

A flooded car will sustain significant damage to its electronics and electrical parts. This typically happens when moisture reaches your car’s electrical system and causes a short circuit. Some of the critical components at risk include:

  • Anti-lock brake system
  • Audio and video systems
  • Air conditioning system
  • Electrical control unit (ECU)
  • Headlights, turn signals, brake lights, and other automotive lights
  • Power locks, power windows, and power seats
  • Fuses

Make sure it is safe to start the engine before you have these electrical components inspected. This simply means taking the necessary steps to completely dry out all the relays, switches, and plugs.

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2. Mechanical damage to the engine

You will likely have some issues with your engine if your car is flooded out. When the water enters certain parts of your engine such as the cylinders and air intake, the piston will attempt to compress it.

Unfortunately, water does not compress, so the piston rods will eventually break and cause engine stalling.

You can easily tell if water has reached your engine if there are water droplets from the oil dipstick and oil that appears milky.

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3. Mold and mildew growth in the interior

After sometime, mold and mildew may develop inside your car if it is not properly dried out. Mold can take as little as 24 to 48 hours to appear given the right conditions (moisture and humidity).

The presence of mold and mildew is often associated with a strong musty odor, and it can trigger respiratory diseases such as allergies and asthma.

Some areas where mold can develop inside your car after being flooded out include:

  • Trunk
  • Door panels
  • A/C system
  • Headliner
  • Floor mats and carpets
  • Seats

It is generally advisable to remove water from your car’s interior as soon as possible to avoid mold growth and mold damage.

Put towels on the seats and floor to soak up the water. You can replace some of the wet parts like seats, door panels, and carpets if incur severe damage.

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4. Debris and mud in hard-to-clean areas

When the floodwater recedes, it can leave debris and mud on areas that are not too conspicuous. These areas include the underbody, brakes, wheels, engine compartment, and spaces under the hood.

Be sure to check for mud or debris in these places and then have the car detailed to make sure it is all clean.

5. Corrosion on different car parts

If your car is submerged in water, rust may form on some of the car parts. This can weaken the structure of your car and compromise important functions such as shifting gears and braking.

So if you notice any sign of corrosion on your car after it was submerged in water, start the process of removing the rust immediately before it spreads to other parts.

Some of the car areas that are highly prone to rust include:

  • Wheel wells
  • Chassis
  • Trunk
  • Fenders
  • Brake pads
  • Clutch
  • Fuel tank
  • Muffler
  • Engine parts
  • Bolts and screws
  • Frame

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6. Contaminated fluids

In some cases, the water may find its way to the coolant reservoirs, power steering, brake fluid, and transmission, where it then blends with your car fluids.

This can seriously affect the performance of your car. For example, when floodwater mixes with fuel, it can cause significant damage to your spark plugs, fuel injectors, and even engine.

7. Slippery brakes

Your brakes may also be affected when immersed in water. The water causes the wet brake rotors and brake pads to part, which in turn results in a loose grip on the brakes.

If your brake pedal feels slippery when you step on it, you should have your brakes inspected by a qualified mechanic.

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FAQs on Car Flooding

Where do cars usually leak during heavy rains?

The weather stripping along your car doors and windows is designed to keep water out of your car, but it can get damaged over time. This causes leaks from where rainwater can penetrate into your vehicle. Even a small leak can lead to severe flooding as water accumulates with time, causing damage to your electrical components, carpets, panels, and upholstery.

How long do I have to escape from a car submerged in water?

You have about 30 to 120 seconds to escape from your car if it is submerged in water. Research has shown that in most cases where a vehicle is submerged in water, the car will float for 30 to 120 seconds before it sinks. If you stay calm and act fast, you should be able to get out of the submerged car in as little as 30 seconds.

Can my auto insurance cover flood damage?

Yes, your car insurance can cover flood damage if you pay for comprehensive auto coverage. Comprehensive coverage helps to pay for repairs or replacements for damages caused by other factors apart from collision, such as flooding. However, your insurance will not cover the damage if a maintenance issue contributed to the car being flooded, for example leaving a car window open when it’s raining.


What happens when a car is submerged in water generally depends on the amount and type of water involved.

If your car has been flooded, do not attempt to start it before it is completely dried out and a technician has done a thorough inspection of all the components.

This is because floodwater tends to work its way into every part of your vehicle, both big and small, and can cause electrical issues that can eventually lead to premature failure. 

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