How to Prevent Frozen and Burst Pipes

Every winter, burst pipes leave UK homes without water, and with repair bills running into thousands. The Association of British Insurers puts the average weather-related home insurance claim for a burst pipe at £9,300.

This is caused by pipes breaking when the water inside freezes and expands, causing the water inside to flow out of the cracks.

The good news is that frozen pipes are preventable, and a registered plumber can help you repair a pipe which has already broken.

This guide explains how to prevent frozen pipes, and what to do if you suspect one has frozen or burst already.

Why do pipes freeze?

Any pipework running through an unheated space is at risk, which usually means lofts, garages, basements, and anything outside, including your outside tap and your boiler's condensate pipe.

A brief dip below 0°C overnight may not freeze the pipe straight away, but sustained cold weather over hours and days can cause the water inside to freeze.

Foam insulation, known as lagging, is cheap and easy to find in most DIY stores, and is key to preventing your pipes from freezing. Our research found that less than 1 in 4 people say they insulate their water pipes to prepare for winter.

Four things make a difference: how exposed the pipe is, whether it's insulated, how long the cold lasts, and whether water is moving through it. Moving water is far harder to freeze, which is why rarely-used outside taps tend to freeze first.

How to Protect Your Pipes Before Winter

Knowing how to prevent burst pipes comes down to six simple checks.

Insulate Exposed Pipes

Foam insulation, also known as lagging, is inexpensive and sold in most DIY shops. Fit it to any pipework in a loft, garage, basement, or outdoor space, and use an insulated cover on your outside tap. If you aren't confident doing it, a registered plumber can fit it for you.

Keep Your Home Warm

Set your thermostat to at least 14°C, including while you're away. If you have a smart thermostat, switch on its frost protection setting, and set any radiator valve showing a snowflake symbol to this setting to keep a minimum flow moving. Leave the heating on at a low setting, and turn the water off at the stop tap if you're away for a long period. Ask a neighbour to look in, and make sure someone can reach you.

Check For Drips and Leaks

A slow drip can freeze and block a pipe, so check taps, visible pipework, and your toilet before the temperature drops. Toilets are the easiest to miss, with up to one in 20 leaking and some losing 400 litres a day, unnoticed. Our guide to spotting a leaky loo shows you how to check yours.

Arrange for a registered plumber to deal with any leaks you find. Plumbing repairs fall under the water regulations, and work done incorrectly can worsen a leak or risk contaminating your supply.

Locate and Test Your Stop Tap

Your stop tap shuts off the water to your home, and it's usually under the kitchen sink, although it can also be in an airing cupboard or utility room. Find it, make sure it turns easily, and check it every six months. We recommend you test it every time you change your clocks in spring and autumn, so you don’t forget.

If you can't locate yours, read our guide to finding your internal stop tap. Our survey shows that 14% of households don't know how to find or use their stop tap. Your stop tap is your first line of defence in a water emergency, so make sure you know where yours is before disaster strikes.

Have Your Boiler and Heating System Serviced

A heating system that fails in a cold snap can leave your home more susceptible to frozen pipes. Book an annual service with a Gas Safe-registered engineer, who will also check the condensate pipe. Boilers fitted since 2005 are usually condensing models, and a frozen condensate pipe is one of the most common causes of winter breakdowns. There's more in our advice on avoiding a boiler breakdown.

Keep a Qualified Plumber's Details Handy

Find a WaterSafe-registered plumber and keep the details safe. We suggest writing the plumber’s name and number on a gift tag and tying it to your stop tap. You can find out more about what to look for when hiring a plumber, and how to avoid rogue traders, including advice by the Trading Standards Institute.

We also recommend isolating and draining any pipework you’re not using, such as outside taps. Ask your plumber for help if you’re unsure on which parts of your plumbing this applies to.

How Do You Know if a Pipe Is Frozen?

There may be warning signs before the pipe bursts, such as:

• Little or no water coming from a tap or shower

• Noticeably reduced water flow

• Gurgling or banging noises from the plumbing

• A boiler that won't fire up, or that shuts itself down and shows an error code

• A toilet that won't refill after flushing

• Damp patches or unexplained water near pipework.

What to Do if You Have a Frozen Pipe

If you have a frozen pipe, the safest option is to turn off the water at your stop tap, then call a registered plumber. 

If you are certain the pipe hasn’t cracked, you can turn your water off at the stop tap and gently hold a hot water bottle onto the frozen section of pipe. Start at the end nearest the tap and work your way back towards the stop tap.

Never apply a naked flame, a blowtorch, or boiling water to a frozen pipe. Rapid heating can split a pipe that’s already weak or expose hidden cracks. Don't leave taps running in the hope of clearing the blockage either; you could waste a lot of water if it starts running unexpectedly.

A registered plumber can locate the frozen section, thaw it safely, and check the pipe for damage before your water goes back on.

What to Do If a Pipe Has Burst

If you have a burst pipe, you would typically see water appearing where it shouldn't: puddles, damp patches on walls or ceilings, or pooling in more than one place at once. If this happens, follow these steps to limit the water waste and minimise damage to your home:

• Turn off the water: shut the stop tap straight away and catch any remaining water draining from the pipe in a bucket or similar. This is the single most effective thing you can do to limit the damage.

• Stay away from electrics: if water has reached sockets, wiring, or appliances, don't touch them. Switch the electricity off at the consumer unit if you can reach it safely.

• Call a registered plumber: burst pipes need a qualified repair. Attempting it yourself can breach the water regulations and risk contaminating your supply.

• Tell your insurer: escape of water is one of the most common home insurance claims, and most insurers want to hear from you quickly.

How Can a Plumber Help With Frozen or Burst Pipes?

A registered plumber can trace the frozen sections of pipe, thaw it without splitting the pipe, repair it safely, and help you protect any remaining pipework which is vulnerable to the cold.

Every plumber on our register is qualified, insured, and approved to work on drinking water systems. You can search by postcode and find someone local in under a minute.

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