How to drive through floodwater

Ever been in that situation where you’re not 100% sure whether you should drive through some floodwater? Don’t worry, we’re about to give you a crash course in how to do it so you don’t have to worry any more. In summary – don’t drive through it if you are not 100% sure. You need to be sure that your car will make it to the other side without getting damaged or leaving you in a potentially dangerous situation.

Summer is coming to an end and in the UK that means only one thing: torrential rain. Prolonged periods of such rain can cause flooding on the roads and inevitable there will be sports where this water doesn’t drain away for whatever reason.

It’s important to note that there are two types of floodwater: flowing and standing. The majority of floodwater you’ll come across in the UK is standing floodwater so our advice refers to this. In a nutshell flowing floodwater should be avoided at all costs, as it only takes about 1ft of flowing floodwater to move a car, which can result in dangerous consequences.

Driving through standing floodwater

As mentioned earlier if you’re in any doubt your best option is not to drive through it. Being late to your destination because of finding an alternative route is far better than the potential damage that you can do to your car (or yourself) if you get things wrong.
If you’re unsure of the depth you can use a stick by dipping it into the water and making a note of how far up the stick the water comes. You can then compare this to your car. As a general rule, if the water is high enough to reach any of the car’s bodywork, then it’s best not to drive through it. Take extra care if entering the water to check the depth. Even a small flowing current is enough to knock someone over, and there may well be hidden obstacles and hazards under the water.
If you’re okay with all of this and still wish to proceed, then follow these steps:

One at a time

It’s best to let the car in front pass the floodwater fully before venturing in yourself. If you follow too closely and the car in front has problems then your vehicle is more likely to be left standing in the water with theirs. Wait your turn and be aware that oncoming vehicles will probably be doing the same.

Drive in the middle

Roads slope towards the sides, so use this to your advantage by driving through the shallower water in the middle. By driving in the middle you also reduce the risk of hitting an unseen kerb or mounting a soft verge.

Drive slow, but make progress

If you’ve ever used a jetwash you’ll know how powerful water can be. If you drive through water too quickly it can easily pull parts off of your car. You could also aquaplane reducing the grip your tyres have on the road, or the high pressure water could damage your engine’s components.
So slow down when driving through the floodwater. But keep up enough speed to create a small bow wave which will reduce the water level slightly. Don’t let the car stop moving until you are clear of the water. If your car has manual transmission, dip the clutch slightly to increase revs.

Keep your revs high

If in a manual car, keep the car in first gear so that the engine speed is higher. If your car is an automatic then lock the engine into a lower gear if possible. By keeping the revs high there is less chance that water will enter via the exhaust pipe, and also reduce the chances of your engine stalling in the middle of the water.

Test your brakes afterwards

When you’ve passed the floodwater, apply your car’s brakes to clear the moisture from them. This will give you peace of mind that they will work effectively when you actually need them.