What to do in the first hour after a water leak

Water is dripping through the hall ceiling. Or you come home to a puddle spreading across the utility room floor. The first reaction is usually panic.

The first hour after a water leak matters a great deal. Every minute the water runs, moisture soaks further into floors and walls. You do not have to do everything at once, just the right things in the right order.

Whether it is a burst pipe or a split hose, this calm, step by step guide shows what to do if you have a water leak. At the end there is a short checklist to print and keep by your stopcock.

1. Turn off the water at the stopcock

The most important step is to stop the water.

Where is the stopcock? It sits where the mains water pipe enters your home. In most houses that is under the kitchen sink. Other common places are the utility room, an airing cupboard, a downstairs cloakroom, under the stairs or in a cellar. In a flat, look in the kitchen or bathroom. There may also be a shared one elsewhere in the building.

How to turn it off. A traditional stopcock with a round handle turns clockwise until it stops. A lever valve needs a quarter turn so the handle sits across the pipe. If an old stopcock is stiff, do not force it. Call a plumber.

Make sure everyone knows where it is. You may not be home when it happens. Show everyone in the household where the stopcock is and how to turn it, including anyone who looks after the house while you are away.

If the leak is clearly coming from one appliance, such as the washing machine, you can often close its own isolating valve. If you are not sure where the water is coming from, use the stopcock.

2. Make the electrics safe

Think about safety before you start mopping.

• If water has reached sockets, light fittings, wiring or appliances, switch off the power at the consumer unit. Use the main switch, or the circuit for the affected area if you are sure which one it is.
• Never touch switches, plugs or appliances while standing in water or with wet hands.
• If the consumer unit is in a room with water on the floor, do not go in. Call an electrician. If there is immediate danger, call 999.
• If water is coming through the ceiling near a light, do not switch that light on.

Have an electrician check any circuit that got wet before you turn it back on.

3. Drain the system and limit the damage

With the stopcock closed, there is still water sitting in the pipes. Open the cold taps, starting at the lowest point in the house, and flush the toilets. This drains the system so less water escapes through the leak.

• Move furniture and rugs away from the water. Raise anything you cannot move on blocks.
• Mop up with towels, buckets and a squeegee.
• Protect valuables such as documents, photos and electronics.
• Do not use a household vacuum cleaner on water. It can be dangerous. Only a wet vacuum designed for water will do.
• Put a bucket under any drip from the ceiling. Do not stand under a ceiling that is sagging with water.

4. Record everything and call the right people

Take photos before you clean up

• Take photos and video of the damage before you mop it all up. Get wide shots and close ups.
• Photograph the cause if you can see it, such as a split hose or a cracked pipe.
• Write down when you found the leak and when you turned the water off.
• Keep any failed parts, like a burst hose or a broken fitting. Do not throw anything away until your insurer says you can.

Call your insurer and a plumber

Contact your insurer as soon as the situation is under control and start an escape of water claim through their claims line. What is covered, and what excess applies, differs between insurers and policies, so check your policy.

Call a plumber to repair the leak. Until it is fixed, keep the water off, or only turn it on briefly when you really need it.

Living in a flat? Contact your landlord, managing agent or building manager straight away. The water may have reached the flat below, or be coming from the flat above, so knock on your neighbours' doors too. Who is responsible depends on your lease and the building's insurance.

5. Do not strip out, and watch the next few days

Leave the drying to the professionals

It is tempting to pull up the flooring or open up the wall straight away. Hold off. Your insurer will often want to see the damage before anything is removed, and stripping out yourself can make it harder to show what happened. Check your policy, or ask when you call.

Drying out after a leak is often handled by a restoration company. They measure the moisture in floors and walls and bring in dehumidifiers and air movers, which can run for weeks. To understand why drying and reinstatement are so often the biggest part of the bill, read about what a water leak really costs.

Ventilate and watch for damp

Moisture that lingers can lead to mould.

• Ventilate regularly, but do not crank the heating up to dry things fast. Let the restoration company manage the drying.
• Watch for damp patches, bubbling paint and floors that start to lift.
• Notice any musty smell, a sign of moisture that has not dried out.
• Wash or dry wet soft furnishings quickly. Anything still damp after a couple of days can start to grow mould.
• Contact your insurer again if new damage appears.

Printable water leak checklist

1. Turn off the stopcock.
2. Switch off the power at the consumer unit if water is near electrics. Never touch electrics while standing in water.
3. Open the taps at the lowest point and flush the toilets.
4. Move furniture, rugs and valuables. Mop up. No household vacuum.
5. Take photos and video. Note the time.
6. Call your insurer and a plumber. In a flat: your landlord, managing agent or building manager.
7. Do not strip anything out before your insurer has seen the damage.
8. Ventilate and watch for damp and mould over the coming weeks.

The sooner you know, the smaller the damage

Everything in this guide starts when you discover the leak. That is rarely when the leak starts. A hose can split while you sleep. A pipe can burst while you are at work or on holiday. The water may run for hours before your first hour has even begun.

Continuous flow monitoring on the incoming mains pipe moves that starting point. Water Grip clamps onto the pipe where water enters your home and measures the flow all the time. When the flow looks wrong, for example a small, constant flow in the middle of the night, it alerts you in the app wherever you are. You can fit it yourself in a few minutes, without a plumber. Water Grip does not turn the water off. You do, or someone you call, at the stopcock. But you know straight away.

If you are weighing up which kind of protection suits your home, compare a water leak alarm with an automatic shut off valve. Whatever you choose, the sooner you know, the smaller the damage. Your first hour should start when the leak starts, not when you happen to find it.