Advice for Fleet Drivers on Driving in Heavy Rain and Floods

Written by John

On September 11, 2020

It can be very hazardous when driving in heavy rain, storms with thunder and lightning, hail and floods.

When driving in bad weather, it always seems to be the time your vehicle wants to play up and brake down. This is because the damp can cause issues with engines and electrical systems. Plus, it is easy to flood your engine when you drive through flood water, incorrectly.

Flood water, you must only drive through if you are sure that it is not to deep. It is best to avoid driving through puddles as you do not know how deep they are, puddles will form in pot holes and could be made worse by being driven over, they are also caused where there is a low camber or blocked drain, no matter how they arrive it is best to go round them if possible. Driving through can cause serious damage to your vehicle. Plus, then an extortionate amount of cost to repair.

If you must drive through follow these 7 steps. 

  1. Try and see how deep it is. Even if that means stopping your car and getting out to look. Being a bit wet now is better than getting stuck and stranded in the water. If it is muddy you may not make it through so best not to risk it as you will not know where the bottom is.


  1. If you think it is too deep, or you are not sure on the depth, you have tried to find how deep it is with a stick, always then try and find another way round to your destination. Door seals are good at keeping water out, but water will eventually find its way in.
  2. If the puddle/flood is shallow enough to drive through and you’re going to give it a go, try and look for objects that may cause damage to your vehicle and leave you stranded in the middle.
  3. Now that you have checked the depth and see no objects, pick your route through, you are going to set off, keep in a low gear, second gear will do, and keep the engine revs up, this will help you keep your momentum when you travel through the flood, creating a bow wave so you do not get bogged down and stuck.
  4. Once you are out the other side pause for a moment if you can safely to let excess water drain away and off your vehicle, especially if it was deep.
  5. When driving away, be aware others may not have paused and now there may be running water along the tarmac from other road users that have passed through, reducing your grip.
  6. Now you will want to get brake performance back, brakes when wet will increase your stopping distance so you will want to gently test your brakes as you move away from the flood, doing so gently causes friction and heat to evaporate any excess water and damp in the brake pads and discs.

Shallow puddles are not so bad to get through so adjust your speed to suit the depth of the puddle/flood and remember you will have less effective brakes the other side and possibly less grip on the tarmac, if the flood was deep take your time and be careful when crossing. Taking your time to assess and plan will take a few minutes and cost nothing, whereas rushing and getting stuck will cost much more than just time.

If it is a flood with fast flowing water never try and drive through as you can easily be swept away.

How Should You Prepare for Driving in Heavy Rain?

  1. Firstly, keep checking the weather as it may not be raining when you set off but in a long journey the weather could change for worse. So, consider the weather and consider is your journey essential? If it is not can it be delayed?
  2. Plan your journey before you set off, I normally doing it in advance say the day before. You can then find places that are prone to flooding and avoid them or allow extra time for the slower speeds and congestion.
  3. If your travelling far, let family, relatives or friends know your journey and intended route and the time you should arrive, plus give them a call once you have arrived. If for work this planning could mean the difference between making a very important meeting or not.
  4. Before you set off, you should always carry out your daily walk round / vehicle safety checks and fill out your report form, card or app. But in addition, these are specific to rain.

These checks are:

  • Check that the windscreen wiper blades are not torn, split or coming off and working correctly, both front and back, if not get them changed. If in an unfamiliar vehicle ensure you know where the switch is to operate them.
  • Fill up with fuel before you get on your way or just as you set off, file consumption will increase when sitting in traffic.
  • Listen to local radio for updates on road closures and flooding.
  • Have your mobile phone in the glove box, fully charged. In case you get into difficulties.
  • Check your tyres for the correct tread depth and pressures.
  • Check your oil and water levels.
  • Check all lights and indicators are working.

You can look up our 6 daily checklist for information on the checks you can do.

How to Drive in the Heavy Rain

  1. Firstly, ensure you know where the wiper switch is if you’re in a works vehicle that is unfamiliar to you.
  2. Reduce your speed. Slow Down. Leave more space between you and the vehicle in front as stopping distances are increased, you may need the extra time to stop if you cannot see a large puddle ahead and the vehicle in front stops quickly.
  3. Use dipped headlights so that others can see you more easily, remember. Daytime running lights will light up your dash, but only have lights on the front not the rear of your vehicle. It is important to be seen from the rear just as from in front.
  4. Do not use rear fog lights, these can mask your brake lights and dazzle drivers that are behind you.
  5. Look out for fast moving vehicles going the other way which may create spray, also large vehicles causing spray which will reduce your visibility as it hits your windscreen.
  6. Use your air conditioning as it will stop your windows from misting you.
  7. If you do break down. Do not open up your bonnet and leave it open whilst you wait on recovery as the torrential rain can further damage the electrical systems once they get wet.
  8. Driving too fast through standing water could lead to tyres losing contact with the road.  If your steering suddenly feels light you could be aquaplaning. To regain grip, ease off the accelerator, do not brake and allow your speed to reduce until you gain full control of the steering again.
  9. By driving too fast through the deep water it can cause serious and very expensive damage to your vehicle.
  10. Be a considerate driver, think of others whilst driving. Try not to create spray on cyclists or pedestrians and do not splash through puddles to soak them.
  11. Heavy rain may lead to large puddles forming fast, so plan and take your time for your safety and that of others.

Your Stopping Distances In The Rain.

Your tyres will have less grip on the road, so as it states in the Highway Code stopping distances double in the wet weather.

In the dry it is the two second rule, four seconds in the wet.

What To Do if You Break Down In The Heavy Rain?

As I mentioned above do not open the bonnet whilst waiting on recovery so not to soak the electrical systems.

If your engine cuts out after driving through a flood, do not attempt to restart it, the water in the engine could cause much more damage, turn on your hazard lights and call for recovery.

Catastrophic flood-related engine damage is typically caused by water being sucked into the engine, which causes the engine to lock up (mechanics call it an ‘air lock’) and can in turn damage important engine components such as piston connecting rods and valves.

This inevitably means a new engine will have to be fitted, but what people generally don’t understand is that it is the owner who is likely to have to foot the expensive garage bill, unless they can demonstrate to their insurer – like in any accident – that it was not their actions that caused the damage.

If this is then your company vehicle will your company then look to recover the costs from you? Causing such damage to a company vehicle, would also be under gross misconduct, this could lead to you being let go from the job.


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