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Protecting Your Car from Flood Damage: 10 Essential Tips for Managing Flash Floods
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Never underestimate flood waters, even if other cars are seemingly driving though without a hitch.
- Always assess the situation before driving through a flooded road
- Even 4x4s can be at risk in flooded areas
- The danger isn’t over as soon as you’re out of the water
What is Flash Flooding?
Flash flooding in the UK is a natural hazard that can occur with little warning, often as a result of lots of rainfall overwhelming the drainage capacity in an area. Flash floods can cause substantial damage to homes, and people.
Floods are also dangerous for cars and their drivers, and we’re facing them more and more often. Even areas such as London which aren’t considered flood zones can experience flash flooding.
Not only can flood water cause irreparable damage to a car’s interior and electrical system, there’s also a risk of water getting into the engine and making it seize.
Fast-moving water can also put drivers at risk – in some conditions, six inches of fast-flowing water can knock you over. There are ways to manage flash flooding and useful tips to prevent dangerous situations, and we’ve put together the following tips to help you drive safely in flash floods.
1. A different route
Before trying to drive through a flooded area, always check to see if there's a different route you can take. Check your route before you leave and only attempt to cross flooded roads as a last resort.
To check if you live or regularly drive in a flood risk area, the Environment Agency provides a valuable online tool. Simply enter your postcode, and you can access up-to-date flood risk information specific to your location. This tool isn’t only essential for drivers who want to be aware of flood zones on their routes, but also to homeowners who want to prepare for any potential damage.
2. Stop and assess
You can never be sure of the depth of water or the state of the road underneath without taking a close look. If you’re crossing at a ford, there may be a water depth gauge at the side of the road, a useful tool which will allow you to assess the stream’s level.
Also look out for other potential hazards that could pose a threat:
- Floating Debris: Objects carried by moving water can damage your vehicle or obstruct your path.
- Downed Power Lines: These pose a serious risk as water can conduct electricity, creating a dangerous situation.
After assessing the surrounding hazards, it's important to consider the best ways to navigate through water you think’s safe to cross.
3. Check the depth
The general rule is that you shouldn’t attempt to drive through standing water that’s more than six-inches deep – so if it comes over your wellington boots, then it’s a no-go.
If it's moving, the maximum depth is even less: any more than four inches of moving water can be enough to sweep a car away into deeper flood water and it can really affect a driver's control and the stability of your vehicle.
Never underestimate flood waters, even if other cars are seemingly driving though without a hitch.
4. Take care when passing other vehicles
When driving through floodwaters, it's important to maintain a clear path and avoid copying other drivers.
Following too closely or attempting to cross paths with other vehicles, particularly large ones, can lead to unpredictable water movement and could force you off course. Large vehicles, such as lorries or buses, can also displace significant amounts of water, generating waves and increasing the risk of water entering your vehicle.
Here are some additional tips to navigate floodwaters safely.
- Maintain a safe distance: Keep a good gap between your vehicle and the one ahead to avoid the effects of their driving.
- Wait your turn: If a large vehicle is crossing, allow it to clear the flooded area before you drive ahead to prevent being caught in its wave.
- Steady speed: Drive at a slow, consistent pace to minimise wave created by your own vehicle.
- Watch for oncoming traffic: Be wary of oncoming cars that could cause waves and be prepared to stop if necessary.
5. Aim for the highest part of the road
Usually the highest part of the road will be in the middle (called the crown), as most roads are designed to let water drain off the sides.
Make sure you also keep your eyes peeled for the following hidden dips such as potholes, gullies and trenches, which are all where the water could suddenly get deeper!
6. Stay in first gear to keep your speed down
It's often recommended to enter the water at 1-2 mph. Hitting the water at speed could cause the car to aquaplane, which is when the wheels lose their traction and the driver loses control.
Aquaplaning can be particularly dangerous as it may cause the vehicle to skid or veer, increasing the risk of accidents. By keeping your speed down, you can manage the vehicle's stability and navigate floodwaters more safely.
7. Keep your car revving
Once in the water, experts recommend trying to keep the revs up. This may avoid water being sucked back into the exhaust, which could lead to engine damage. If you accelerate to four or five miles per hour, this will create a small wave, protecting your car's engine from the worst of the water.
If you drive a manual and you find keeping the revs high is making you go too fast, try slipping the clutch. This allows you to manage the engine's output and keep the vehicle moving at a safe, steady pace through the water.
8. What to do if you stall
If you stall, it's important to try and start your car straight away, as the longer you wait, the further the water will be creeping up your exhaust system.
9. Dry your brakes
It's important to remember if you've driven through water, it's possible your brakes will be wet and in order for them to work properly you need to dry them.For the next few miles, drive slowly and regularly apply the brakes lightly to heat them up and help the water to evaporate.
10. What to do if your car stops
If your car does stop in the flood, you should try and climb out and lock the doors before wading to solid ground. Take care – there may be uneven surfaces or hazards beneath the water. If you're concerned for your personal safety, phone the Emergency Services.
The extent of flood damage on your car can vary. Minor flooding around the tyres can be repaired, but significant water damage, especially if it’s gone up to the dashboard level, could be beyond repair.
We’d recommend that a professional mechanic looks at the vehicle once the situation is safe. Above all, remember that while cars can be repaired or replaced, your safety is what's most important!
What could happen to my car in flood?
- Mechanical Failure: Firstly, the air intake on cars are at various heights, so even if the car in front makes it through, your in take could be lower and suck water up into the engine.
If water gets into the engine block, it'll very likely cause damage to the pistons con rods, which'll cause it run poorly or not at all! Either of these scenarios could end with a complete engine rebuild or in most cases a new engine. - Electrical Faults: If flood water enters the passenger compartment, it's likely to fill up the footwells. Under the carpets of your car you'll find the wiring harness. These have many connectors and the ECU’s that control the electrical components in your car. If they get wet, you'll probably get electrical issues such as dashboard fault lights, faulty windows and maybe even the car not starting at all!
Issues can happen instantly or take a while to surface as the wiring system starts to corrode. Either way, it'll mean expensive repairs to the electrical systems. - Health Issues: The final point to remember is the water that entering your car is not going to be clean and fresh. It'll be contaminated from drains or road surfaces. In rural locations it could be even worse, if it's come from local fields which have had pesticides used on them. Both of these could cause health issues if not dealt with correctly.