Frozen pipes: how to thaw them and what to do to avoid burst pipes

Freezing weather and snow can be a downer at the best of times, but add frozen pipes into the mix and you are in for a rough winter, especially if one bursts. 

A harsh frost can very quickly, and often unexpectedly, freeze water solid in pipes. This leads to cracks or breaks appearing in the pipes, followed by water leaks either dripping or worse, cascading, down and through a house, damaging decor and furnishings, flooring, and blowing plasterwork and electrics as it goes.

Knowing when to worry about pipes freezing and taking some preventative measures to stop them is the best bet. But, in the case of an emergency, this is how to thaw frozen water pipes and prevent them from bursting, according to the experts. 

How to thaw frozen water pipes

When preparing a house for cold weather you should familiarize yourself with the location of your mains water shut-off values and the general layout of your pipework so that you can treat frozen pipes if and when they occur.  This may seem over the top, but it will be essential knowledge when your water blocks up, or worse, a pipe bursts. 

With that knowledge to hand, you can unfreeze pipes quickly and efficiently.

A step-by-step guide to thawing frozen pipes

1. Turn the water off at the mains

If a pipe becomes blocked with ice, you need to stop any additional water being supplied to your home. This stops pressure from building up which can cause the pipe to burst. 

'As a homeowner, it is best to know where all of your water isolation valves are located,' begins Bill Bruininga, a professional plumber at Go Billys plumbing services. 'You have one at the street, one at the house, and two at each faucet location. Testing the use of each regularly helps when it comes to a pipe burst. Generally speaking, all houses should have these items.

'The street shut-off is designed to turn all water off to your property. If you cannot find a shut-off to isolate the leak, use this street shut-off. You may need a special water key.

'At the house, you should have two shut-offs. One is for irrigation, and one is for housing domestic water. Irrigation shut-off controls all of the outside water for sprinklers. The House line controls all of the plumbing inside the house.'

2. Gently introduce heat to the pipes

The next step is to remove the blockage. Of course, you can't open up a frozen pipe and dish the ice out, so you need to gently introduce heat – especially if you haven't insulated pipes. 

There are various ways to do this – a hot water bottle filled with warm to hot (not boiling) water and tied to the frozen section of the pipe will start the job. Or, you can pour a jug of warm – again, not boiling, which might make the pipe crack – water over the frozen pipe to melt the ice. Similarly, a face flannel or towel soaked in warm water wrapped around the pipe (and refreshed regularly) will help thaw the frozen water inside.

Alternatively, hot air aimed at a frozen pipe can thaw it gently. Don’t allow the pipe to become too hot too quickly to avoid cracking, and be sure to keep the hairdryer away from water.

Finally, using a portable space heater near the frozen pipe can warm the room enough to thaw it gently when you have to turn the heating off. Once the pipes are defrosted and the water is flowing again, you can turn your home heating back on to help defrost any lingering ice.

3. Revisit your home insurance

Many homeowners don’t have plumbing as part of their home insurance – now is the time to check yours covers frozen and burst pipes or boilers damaged by freezing conditions. 

How to prevent frozen water pipes in future

Prevention is always better than a cure, especially regarding something as potentially damaging as frozen pipes. Luckily, there are some simple steps you can take to prevent a freeze-up, even in the coldest of winters:

1. Keep the water in the pipes warm

Frozen pipes can happen in a matter of hours. Even turning your heating off overnight can lead to blockages in the right weather conditions. 

'Don't let your home or business’s indoor temperature get below 40 degrees Fahrenheit — if your heat turns off and the water inside your pipes freezes, they'll be more likely to burst,' warns Peter Duncanson, director of training and development at ServiceMaster Restore. 

2. Keep the water in the pipes moving

If freezing weather is forecasted, keeping the water moving will stop pipes from freezing. You can do this by regularly running water through taps – especially exposed ones, perhaps outdoors. Dripping faucets will help stop the water in the pipes from freezing. 

3. Insulate pipes to stop them freezing

Pipes that are not connected to a warm water supply should be insulated to help prevent them from freezing, suggests Mark Snell, CEO of Polestar Plumbing, Heating & Air Conditioning.

'Prioritize insulating pipes in unheated areas of your home to prevent freezing,' he recommends. 'Such areas include attic, basement, crawl spaces, and any other spaces where pipes are exposed to cold temperatures, to prevent freezing.'

You can also try leaving an attic door open during a freeze to help regulate your roof temperature and protect your pipes. 

4. Keep your home’s cold spots warm

If you have an unheated closed front porch, boot room, or pantry with water pipes in them, ensure the pipes are insulated or – as a short-term fix – leave an adjoining door that leads to a heated room indoors open. Better to be chilly for a day while you work on getting the insulation done than suffering burst pipes. Similarly, garage doors should be kept shut if there is a water supply there too.

5. Invest in a smart thermostat

Some smart thermostats do more than control your heating and make your heating more efficient, they can also monitor your heating system and let you know if your pipes are in danger of freezing before it happens. 

If your smart thermostat doesn't do this, you can also consider smart sensors. This smart tech can combat frozen pipes before they become a problem. Grohe’s Sense and Sense Guard, from Amazon, for example, can monitor the temperature of incoming water and detect leaks in key places in your home – which it will then notify you about with a message to your smartphone. If fitted on a mains water pipe, it will even let you switch off your water supply remotely. And you can set it to detect burst pipes automatically and turn off the water supply for you.  

Signs your pipes have frozen

There are a few signs your pipes may be freezing through that can give you an early warning ahead of a full freeze: 

• Your taps or drains are giving off an unpleasant smell. 
• The water runs weakly from the taps. 
• There is frost on the outside of the pipes. 
• If boiler pipes are frozen, you might notice a gurgling noise and an error message. Always alert a professional to help you with this.

FAQs

How long do frozen pipes take to thaw?

When manually defrosting frozen pipes, it can take 30 to 60 minutes for water to start flowing normally again. Even if your water pressure has been restored, it is a good idea to continue to gently heat your pipes to ensure there is no stubborn ice remaining that can cause your pipes to freeze over more quickly. 

Will frozen pipes thaw on their own?

Frozen pipes can thaw on their own, but it can take a long time and will only occur once temperatures reach higher than freezing point for a sustained period of time. It is generally a better idea to prevent pipes from freezing in the first place or defrost your pipes manually to avoid bursts. 

If the worst comes to the worst, it is important to also educate yourself on what to do if a pipe bursts. Although following these remedies and preventative measures should help fend off a worst-case scenario, having a plan in place for a water leak can help to avoid panic in the moment and ensure a rapid and smooth solution.