Black Volvo XC40 parked on a wet suburban residential street - aquaplaning

Aquaplaning: what it is and how to avoid it

Aquaplaning (also called hydroplaning) occurs when a tyre cannot channel water out of its tread fast enough to maintain contact with the road. The result is a sudden loss of steering and braking response. It can happen quickly and without warning, but the risk is manageable with the right tyres, correct speed and good technique.

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What is aquaplaning?

Aquaplaning occurs when a layer of water builds up between a tyre and the road surface faster than the tyre can clear it. The tyre effectively rides on a film of water rather than gripping the tarmac beneath. When this happens, the tyre loses its ability to steer, brake or accelerate the vehicle - the car is briefly travelling on water with no mechanical connection to the road.

The experience for the driver is distinctive. The steering feels suddenly light, as if it has lost resistance. The car may begin to drift in a direction not intended, or feel as though it is floating. In modern vehicles with ABS and stability control, warning lights may activate as the systems detect wheel-speed anomalies.

What causes aquaplaning?

Three factors drive aquaplaning risk:

Speed: The faster the vehicle, the less time the tyre has to channel water away from the contact patch. Aquaplaning risk increases significantly above 50 mph in heavy rain, and becomes a serious concern at motorway speeds in deep standing water.

Water depth: Shallow surface water rarely causes aquaplaning. Standing water at junctions, dips in the road, and water running across the carriageway are the higher-risk scenarios. The UK's road surfaces age and sag, creating channels where water accumulates.

Tyre condition: A tyre with deep, open tread grooves can channel significantly more water per second than a worn tyre with shallow, compressed grooves. A tyre at the legal minimum tread depth of 1.6mm has a fraction of the water-clearing capacity of a new tyre. Tyre pressure also matters - an under-inflated tyre has a larger, flatter contact patch that channels water less efficiently.

How to recognise aquaplaning

The main signs are:

Sudden lightness in the steering - the wheel becomes easy to turn but the car does not respond as expected
A sense of floating or drifting, often with a slight vibration
The engine revs rising if the driven wheels are spinning without grip (on a rear-wheel-drive or front-wheel-drive vehicle)
ABS or stability control warning lights on the dashboard

Aquaplaning often resolves within seconds as the tyre finds grip again, but those seconds are enough for the vehicle to drift significantly off course.

What to do if you aquaplane

The instinctive reaction is to brake or steer sharply - both of which make the situation worse. The correct technique is:

Ease off the accelerator smoothly - do not stamp on the brakes.
Hold the steering wheel straight and avoid large inputs.
Wait for the tyres to regain contact with the road surface. This usually takes only a second or two.
Once grip returns, gently apply the brakes if you need to reduce speed.

If the rear of the vehicle begins to slide, apply a small amount of opposite lock (steering in the direction of the slide) to correct it - the same technique as any rear slide.

set of car keys on a wooden kitchen table next to a folded blank newspaper - aquaplaning

How to reduce the risk

Slow down in rain: Reducing speed is the single most effective action. The tyre's ability to channel water at 40 mph is much greater than at 70 mph on the same wet surface.

Maintain tyre tread: New tyres have tread depths of around 7 to 8mm. At 3mm, water-clearing capacity is significantly reduced. At the legal minimum of 1.6mm, aquaplaning risk is substantially higher. Replacing tyres before the absolute minimum is reached improves wet weather safety measurably.

Check tyre pressure: Under-inflated tyres are more prone to aquaplaning. Our guide to checking tyre pressure correctly covers how to check and what the correct pressure for your vehicle is.

Avoid following tracks: Other vehicles' tyres clear some water from the road surface. Driving in the wheel tracks of the vehicle ahead leaves less standing water in your tyre's path.

Rain and wet roads: the broader picture

Our guide to driving in bad weather covers stopping distances, reduced visibility, and how to adjust your driving in adverse conditions beyond just wet roads. Aquaplaning is one of several wet-weather hazards that become easier to manage with a combination of good tyre condition, appropriate speed and awareness.

Panning shot of a silver estate moving through a central London street - aquaplaning

Short-term cover for any vehicle

If you are driving a borrowed car or a vehicle you do not normally use, check that the tyres are in good condition before any wet-weather journey. Temporary car insurance gives you comprehensive cover for the time you need it - and a quick tyre inspection before setting off is always worthwhile.

Frequently asked questions

What causes aquaplaning?

Aquaplaning is caused by a tyre being unable to channel water out from under its contact patch fast enough to maintain grip. The three main contributing factors are speed (higher speed reduces the tyre's time to clear water), water depth on the road surface, and tyre condition - worn or under-inflated tyres are significantly more vulnerable.

What should you do when aquaplaning?

Ease off the accelerator smoothly and hold the steering wheel straight. Do not brake hard or make sharp steering inputs - both make the situation worse. Wait for the tyres to regain contact with the road, which usually takes a second or two, then gently apply the brakes if needed.

At what speed does aquaplaning occur?

There is no fixed threshold - it depends on the depth of standing water, tyre condition and road surface. Risk increases significantly above 50 mph in heavy rain on a wet road, and becomes a serious concern at motorway speeds on any standing water. Slowing down is the most effective preventive measure.

Does tyre tread depth affect aquaplaning risk?

Yes, significantly. Tyre tread grooves are designed to channel water away from the contact patch. At the legal minimum of 1.6mm, a tyre clears far less water per second than one with 4 to 7mm of tread remaining. Replacing tyres before the absolute minimum substantially reduces wet-weather aquaplaning risk.

Is aquaplaning common in the UK?

Aquaplaning is a real risk in the UK given the frequency of wet weather. It is more common than many drivers realise because it is often brief - a second or two of reduced grip before the tyre finds the road again. Most drivers who have experienced it may not have recognised it as aquaplaning.