How to stop pipes freezing and what to do if one bursts

A frozen pipe is one of the most common winter call outs, and a burst one can do serious damage in the time it takes to find the stop tap. The good news is that most of the prevention is cheap, and most of the damage limitation is something you can do yourself in the first five minutes. This guide covers how to protect your pipes before a cold snap, how to tell if a pipe has frozen and thaw it safely, exactly what to do if one bursts, who is responsible for which pipes, and what your insurer will want to see.

It matters more than it might seem. In 2024 home insurers paid a record £585 million for damage to homes and belongings from storms, flooding and frozen pipes, according to the Association of British Insurers. And WaterSafe, quoting Zurich insurance figures, puts the average cost of repairing household damage from burst pipe leaks at nearly £13,000.

Find your stop tap before you need it

The single most useful thing you can do this winter takes two minutes. The internal stop tap, also called a stopcock, turns off the mains water to your home. It is usually under the kitchen sink, and otherwise in a cupboard, utility room, downstairs bathroom, garage or cellar, close to where the supply pipe comes into the house. In some flats it is in a communal cupboard or the hallway.

• Find it now and make sure everyone in the house knows where it is.
• Test it. Turn it clockwise to close it, check the kitchen cold tap stops, then open it again. Stop taps are rarely used and can seize. WaterSafe suggests checking yours still works every six months.
• If it will not turn, do not force it with a wrench, as old valves can snap. Ask a plumber to free it or replace it. It is a small job, and much cheaper than finding out during a burst.
• Know where the outside stop tap is too, usually under a small cover in the pavement or front garden. You may need a special key, and in an emergency your water company can help.

How to stop pipes freezing

WaterSafe says pipes are at risk once temperatures drop below 0°C. Pipes in heated rooms are rarely the problem. The ones that freeze are in cold spaces: the loft, the garage, outbuildings, cellars, under suspended floors, and anything running along or through an outside wall.

Lag exposed pipes

Severn Trent calls lagging one of the best things you can do to protect your pipes. Foam pipe lagging is sold at DIY stores all year, comes in self-sealing lengths sized for the standard 15mm pipe, and goes on in minutes. Make sure there are no gaps, especially at bends and joints, and tape the joins so cold air cannot reach the pipe. Lag the cold water tank in the loft as well, but not underneath it, so a little warmth can rise from the room below.

Protect outside taps

An outside tap is usually the first thing to freeze, and Severn Trent warns that a frozen tap can increase the risk of a burst pipe. Fit a tap cover from a DIY store and lag the pipe leading to it. If the tap has its own isolating valve inside the house, turn it off for the winter and open the outside tap to drain it.

Keep some heat in the house

• Keep the heating on low in a cold spell, or set it to come on at intervals, even when you are out. If you have a smart thermostat, WaterSafe suggests using its frost or anti-frost setting.
• Open the loft hatch a little on very cold nights so warm air reaches the pipes and tank.
• Open cupboard doors under sinks on outside walls so warm air reaches the pipes.
• Fix dripping taps. A constant drip into a cold pipe or waste can freeze and block it.

Going away in winter

If the house will be empty for a few days in cold weather, Severn Trent suggests turning the water off at the stop tap, so any burst does far less damage. Leave the heating on a low or frost setting if you can. Check your home insurance too: some policies limit cover for escape of water if the home was left unoccupied and unheated.

How to tell if a pipe is frozen

The usual signs are a tap that gives a trickle or nothing at all, a toilet cistern that will not refill, gurgling from the heating, and frost on pipes in the loft, garage or cellar. A boiler that stops in freezing weather is often a different problem, a frozen condensate pipe, covered in our guide to what to do when your boiler breaks down.

Before you start, Severn Trent suggests asking a neighbour. If their taps work, the problem is almost certainly frozen pipes in your home. If they have no water either, it may be a supply problem in the area, so contact your water company rather than a plumber.

How to thaw a frozen pipe safely

Thawing a frozen pipe is a job most people can do themselves, as long as the pipe is easy to reach and you go slowly. The steps from WaterSafe and Severn Trent are:

1. Turn off the water at the stop tap. If the pipe has split under the ice, this stops a flood when it thaws.
2. Open the tap the frozen pipe feeds, so melting water and pressure have somewhere to go.
3. Warm the pipe slowly. Use a hot water bottle wrapped in a cloth, towels soaked in hot water, or a hairdryer on a low or medium setting. Start at the tap end and work back towards the frozen section, keeping the heat moving.
4. Never use a naked flame or blowtorch, and do not pour boiling water on a pipe. Both can crack pipes and joints, and a flame is a serious fire risk in a loft.
5. Check for leaks. Once the water is flowing, run a dry cloth along the pipe. If it comes away wet, turn the water off again and call a plumber.
6. Turn the water back on at the stop tap and check the flow. If there is still no water, a plumber will need to find where the blockage is.

Only thaw pipes you can reach safely. If the frozen section is under a floor, inside a wall or somewhere you cannot see, WaterSafe says it is best to call a plumber.

What to do if a pipe bursts

Speed matters most here. Every minute the water runs adds to the damage, so work through these steps in order, following WaterSafe's burst pipe advice:

1. Turn off the water at the stop tap, clockwise until it stops.
2. Switch off the central heating and boiler, and any immersion heater, so water stops circulating.
3. Open all the cold and hot taps to drain the water left in the pipes and take the pressure off. Flush the toilets.
4. Make the electrics safe. If water has reached light fittings, sockets or the consumer unit, do not touch them. Switch the electricity off at the consumer unit if you can reach it without standing in water, and have an electrician check everything before it goes back on.
5. Limit the damage. Catch drips in buckets, soak up water with towels, move furniture and valuables, and if you live in a flat, warn the neighbours below.
6. Record everything. Take photos and videos of the leak and the damage before anything is moved or thrown away. Your insurer will want them.
7. Call a plumber for a permanent repair. Tape and cloth wraps are a stopgap, not a fix.

A bulging or stained ceiling is a sign water is collecting above it. Stay out from underneath it, keep the electrics off in that room, and tell the plumber when you call.

Who is responsible for a burst pipe?

It depends where the pipe is. In the Severn Trent area, which includes Birmingham, Coventry and much of the West Midlands, the water company is responsible for maintaining the public pipework, and the homeowner must maintain the pipes and taps within the property boundary. In practice:

• Water coming up in the road or pavement is usually the water company's to fix. Report it on their emergency line. Severn Trent's 24 hour number is 0800 783 4444, and other water companies list theirs on their websites and bills.
• A burst inside your home or garden is yours to repair, and to claim for on your insurance if you are covered.
• Tenants should report a burst to the landlord or letting agent straight away, in writing as well as by phone. The landlord is usually responsible for the pipework, but you are expected to turn off the water to limit the damage.
• Flats often have shared pipes, so tell the managing agent as well.

Burst pipes and home insurance

Most buildings and contents policies cover sudden escape of water, which includes a pipe that bursts after freezing. The details vary, so when you check your policy, look for:

• The excess. Escape of water often has a higher excess than other claims.
• Trace and access. This pays to find a hidden leak, for example lifting floorboards or tiles. Not every policy includes it.
• Unoccupancy rules. Some policies limit cover if the home was empty and unheated for a set period.
• Gradual leaks. A slow leak that has been going on for months is often excluded, which is another reason to act on damp patches early. Our guide to whether it is condensation, damp or mould helps you tell what a patch is.

Report the claim as soon as you can, keep receipts for emergency repairs, drying equipment and any alternative accommodation, and keep the plumber's invoice saying what failed and why. WaterSafe also advises keeping records of the damage and the repairs.

Choosing a plumber for a burst pipe

A burst pipe is a genuine emergency, which is exactly when people get overcharged. Our guide to what counts as a plumbing emergency covers who pays and the warning signs of a rogue trader. Ask before anyone sets off:

• what the call out charge is, and whether it includes the first hour;
• the hourly rate, or a fixed price for the repair if they can give one;
• whether evening or weekend rates apply;
• whether they are on an approved register. Severn Trent and WaterSafe both point homeowners to plumbers on the WaterSafe register, who are qualified to work on the drinking water in your home.

Our guide to how much a plumber charges per hour covers typical day, evening and emergency rates, and how to check a tradesperson is genuine shows what to look for before you let anyone in. If the leak has damaged the boiler or heating, any gas work must be done by a Gas Safe registered engineer.

Find a local plumber

If a pipe has frozen or burst, post your job free and hear back from a local plumber. Mark it as an emergency on the last step, tell them where the pipe is and what you have done so far, and the business you choose can come back to you with a price. You pay them directly, and there is nothing to pay online.

Or browse local businesses: plumbers in Birmingham, plumbers in Wolverhampton, plumbers in Coventry, plumbers in Walsall, plumbers in Dudley or plumbers in Solihull. For more winter guides, see all our home advice.