When you have to pass through a flood, take your time. Stop and assess how deep the water is. Do not just drive into it. Some roads that are likely to flood have depth gauges. Check the depth on these.
If the water seems too deep for your vehicle, turn back and go around the flood by using another road. It might take a little longer, but that’s better than finding yourself stranded.
If the water is too deep, it could
- flood the exhaust, causing the engine to stop
- find its way into the air intake on some vehicles, causing serious engine damage.
If the water is not too deep, drive on slowly but be sure to keep to the shallowest part. Remember, because of the camber of the road, the water is probably deepest near the kerb and shallowest at the crown.
Driving through floodwater
Drive in first gear as slowly as possible but keep the engine speed high and steady by slipping the clutch.
If the engine speed is too low, you might stall.
If you go too fast, you could create a bow wave. Water will flood the engine and it could cut out.
Try to strike a balance.
Test your brakes
Water can reduce the effectiveness of your brakes, so test your brakes whenever you’ve passed through water on the road. When you’ve driven safely through, check the mirrors first, and then test your brakes.
If they do not work properly, it will help to dry them out if you apply light pressure to the brake pedal while driving along slowly. Do not drive at normal speed until you’re sure they’re working properly.