How to Protect Your Car From Flood Damage
What flood damage does to a car and why prevention matters
Floodwater damages a car in ways that are not always visible at first. Water gets into the engine, transmission, electrical systems, and interior, causing rust, corrosion, and mechanical failure that can take weeks or months to show up. A car that runs fine after sitting in water for a few hours may stall without warning days later, or develop electrical problems that are expensive to diagnose and repair.
The best protection is not letting your car sit in floodwater at all. If you know flooding is coming or you are driving in an area where water is rising, moving your vehicle to higher ground or staying off the road entirely prevents most of the damage. Once water has entered a car, the repair costs are often high enough that insurance companies total the vehicle — meaning they declare it a loss and pay you the cash value rather than fix it.
Key Takeaways
- Move your car to higher ground before water reaches the road, because even shallow moving water can sweep a vehicle off the road or cause internal damage.
- Do not drive through flooded roads under any circumstances — water depth is hard to judge, and moving water is stronger than most drivers expect.
- If your car is already flooded, do not start the engine, because water in the engine causes damage that spreads the longer it runs.
- After floodwater recedes, have a mechanic inspect the engine, transmission, and electrical systems before you drive the car regularly.
- Comprehensive insurance covers flood damage, but collision insurance does not — check your policy now so you know what is covered.
Moving your car before water arrives
The time to move your car is before the water reaches your street. If your area is under a flood watch or warning, or if heavy rain is forecast for low-lying neighborhoods, move your vehicle to a parking lot or garage on higher ground. This is not the same as moving it a few blocks away — move it to a part of town that does not flood, or to a parking structure where the car will be above ground level.
If you live in an area that floods regularly, know ahead of time where you can move your car. Identify a friend or family member in a higher area who will let you park there, or find a parking garage or lot that stays dry. Do this before a storm arrives, not when water is already rising. During an actual flood event, roads may be closed and you may not be able to reach your usual parking spot.
Check local flood maps to understand which parts of your neighborhood are at risk. South Carolina Emergency Management Division and your county emergency management office both publish flood zone maps online. If your home or regular parking area is in a flood zone, make a plan now for where your car will go when heavy rain is forecast.
Why you should never drive through flooded roads
Floodwater on a road is more dangerous than it looks. Water that is only a foot deep can sweep a car off the road. Water that is two feet deep will float most vehicles. You cannot see what is under the water — the road may be washed out, or debris may be floating just below the surface. Even if the water looks shallow and slow-moving, the current is strong enough to push a car sideways or downstream.
Drivers who try to drive through flooded roads often stall in the middle of the water. If the water is moving, the car can be swept downstream with the driver still inside. If the water is deeper than expected, the car fills with water and the doors become impossible to open because of water pressure. Rescue is difficult and sometimes fatal. The safest choice is always to turn around and find another route, even if it takes much longer.
If you are caught in rising water while driving, get out of the car and move to higher ground immediately. Do not stay in the vehicle hoping the water will recede. Do not try to swim or wade through the water — the current is too strong. Once you are on higher ground, call 911 and wait for rescue.
What to do if your car is already in floodwater
If your car is parked in water or has been driven through floodwater, do not start the engine. Starting the engine when water is inside it causes the water to be drawn into the cylinders, which damages the engine severely and spreads the damage to other systems. This is called hydro-locking, and it can happen even if the water level is not very high.
Turn off the engine immediately if you are driving and the car stalls in water. Do not try to restart it. Get out of the car and move to higher ground, then call for help. If the car is parked and you discover it has been in floodwater, leave the engine off and call a tow truck to move it to a mechanic or repair shop.
Once the car is out of the water, do not drive it until a mechanic has inspected it. The mechanic will check the engine, transmission, electrical system, and interior for water damage. Some damage is obvious — water in the oil, corrosion on battery terminals, mud in the cabin. Other damage takes time to show up. A mechanic can tell you whether the car is safe to drive or whether the damage is too extensive to repair.
Checking your insurance coverage for flood damage
Flood damage is covered by comprehensive insurance, not collision insurance. Comprehensive covers damage from weather, water, fire, theft, and other events that are not caused by a crash. Collision covers damage from hitting another car or object. If you have only collision insurance, flood damage is not covered, and you will have to pay for repairs yourself.
Check your insurance policy now to see what coverage you have. Your insurance company or agent can tell you whether comprehensive is included and what your deductible is. If you do not have comprehensive insurance and you live in an area that floods, adding it may be worth the cost. The premium is usually low, and it covers not just flooding but also hail, wind damage, and other weather events.
If your car is damaged by flooding and you have comprehensive coverage, contact your insurance company as soon as possible. Take photos of the damage and the water level if you can do so safely. Do not drive the car or start the engine before the insurance company has seen it, because doing so may affect your claim. The insurance company will send an adjuster to inspect the car and decide whether to repair it or declare it a total loss.
Drying out and inspecting the car after floodwater recedes
After floodwater has receded and the car is out of the water, the drying process takes time. Open all the doors and windows and let air circulate through the car. Remove floor mats and seat covers so water underneath can dry. If the interior is wet, use fans or a dehumidifier to speed up drying. Do not use heat, because heat can damage electrical components and upholstery.
Have a mechanic inspect the car before you drive it regularly. The inspection should include the engine oil (which may be contaminated with water), the transmission fluid, the battery and electrical connections, and the undercarriage for rust and corrosion. The mechanic should also check the brakes, because water in the brake lines can make brakes fail. If the car has been in saltwater or brackish water, corrosion will happen faster than with freshwater.
Even after repairs, a car that has been flooded may have problems that show up later. Electrical gremlins, rust in hidden places, and mold in the air conditioning system can develop weeks or months after the flooding. Keep records of all repairs and inspections, and report any new problems to your mechanic or insurance company right away.
Preparing your car for flood season
If you live in an area that floods regularly, prepare your car now. Keep your gas tank at least half full during flood season, so you have fuel to drive to higher ground if you need to leave quickly. Make sure your battery is in good condition and your wipers work well, because you may need to drive in heavy rain. Check your tires for good tread, because wet roads are slippery and worn tires lose grip.
Keep your insurance information and your mechanic's phone number in your car or on your phone. If flooding happens, you will need to contact your insurance company quickly, and you will need a mechanic who can tow your car and inspect it. Know the flood zones in your area and plan your routes to avoid them when heavy rain is forecast.
Store important documents related to your car — the title, registration, and insurance policy — in a waterproof container at home, not in the car. If your car is damaged by flooding, you will need these documents to file an insurance claim or sell the car to a salvage company.
Frequently Asked Questions
Can I drive through water if it is only a few inches deep?
No. Even shallow water can damage your car's engine and electrical system, and you cannot judge the depth or current from inside the vehicle. Water that looks shallow may be deeper than it appears, or the road underneath may be washed away. The only safe choice is to turn around and find another route.
What should I do if my car stalls in floodwater while I am driving?
Get out of the car immediately and move to higher ground. Do not try to restart the engine or stay in the vehicle. Call 911 if you cannot reach higher ground safely on your own. Once you are safe, call a tow truck to move the car.
Does my insurance cover flood damage if I drove through water on purpose?
Insurance policies vary, but most comprehensive coverage will not pay if you drove through flooded water knowingly and caused the damage yourself. The policy covers flooding that happens to your parked car or flooding you could not avoid. Check your policy or call your insurance company to understand what is and is not covered.
How long does it take for a flooded car to dry out?
It depends on how much water got inside and how warm and dry the air is. A car with water only in the carpet may dry in a few days with good air circulation. A car with water in the engine or transmission may take weeks, and some damage may be permanent. A mechanic can tell you what to expect after inspecting the car.
Is a car that has been flooded safe to drive after repairs?
It depends on the extent of the damage and the quality of the repairs. A car with minor water damage that was dried and inspected quickly may be fine. A car that sat in water for days or weeks may have hidden rust and electrical problems that show up later. Have a trusted mechanic inspect it thoroughly before you rely on it for regular driving.