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Driving in Flood Water

Posted: 25/08/22

This blog has been written by a member of the Newground Flood Team.

Heavy downpours, prolonged rainfall and blocked or overwhelmed drainage systems can all contribute to the flooding of roads. Flooding can hit fast and cover large areas with water quickly, causing disruption to travel and possibly danger to life.


Paving over urban areas has severely restricted the grounds ability to drain rain water sufficiently, and combined with the limited capacity of sewers and drainage systems, it can mean surface water runoff has nowhere else to go. This leads to standing water on small lanes, roads and motorways which may remain in place for several hours before it can slowly drain away.

Ideally you should not attempt to drive if the roads are flooded. Instead, you should move your vehicle to higher ground to avoid any damage when it is safe to do so – this may be when a weather warning or flood warning has been issued.

Image: The Flood Hub


If you feel that driving is unavoidable in severe weather conditions or if you are perhaps caught in heavy downpours and flash flooding, consider these points:

Check the news

Regional news bulletins will provide information about road closures and localised flooding. The Met Office will have live weather forecasts for the area and the Environment Agency’s flood alerts and warnings may be issued.

Delay the journey

Is it possible to delay the journey or take an alternative route to avoid the flooded area? Keep in mind that you may also need to account for extra journey time for slower speeds.

Water depth

If the depth of water is sufficient to allow water to enter the engine this may cause catastrophic damage and lead to hefty repair bills. It is advised that motorists do not enter flood water that is moving or more than 10cm (4 inches) deep.

  • In standing water, research shows that as little as 30cm (11 inches) of water can cause vehicles to lose contact with the ground, leading to a loss of control.
  • In flowing water, a depth of 60 cm (23 inches) can carry a vehicle away.
  • In deeper water there could also be hidden dangers and hazards that can’t be seen such as missing manhole covers or pot holes.


3-4 mph is recommended by Green Flag!

Have some consideration for other road users and pedestrians. Drive at low speed to avoid or reduce bow waves, as these can flood other vehicles and cause greater amounts of water to enter properties, adding to flood damage. Driving at a lower speed also reduces the potential danger of floodwater to pedestrians as it may be contaminated or contain debris that could cause harm. Leave more space than usual between you and the car in front to reduce the chance of an accident, as stopping distances are increased in wet conditions.

Other things to consider

  • Be careful of aquaplaning. This is when your tyres lose contact with the road surface and you lose control of steering. If this happens, hold the steering wheel lightly and ease off the accelerator to gradually slow down and help your tyres grip the road again.
  • Prepare for the possibility of a breakdown. Make sure you phone is charged so you can call for help and keep an emergency kit in your car containing water, food and warm clothes in case you are stuck for a while.
  • If driving in flood water is avoidable, don’t take the risk.

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Sources: RAC, Green Flag SMART DRIVING, AA