Glossary · Plumbing and water
What should I do about frozen pipes?
Frozen pipes are water pipes in which the water has turned to ice, blocking the flow. You may see frost on the pipe and find taps running slowly or not at all. A frozen pipe can crack and burst as it thaws, so turn off the stopcock, thaw it slowly with warmth and check for leaks.
Key points
- Signs are frost on the outside of a pipe and taps that slow to a trickle or stop.
- Turn off the stopcock, open a cold tap, then thaw slowly with a wrapped hot water bottle or warm towels.
- Never use a blow torch or naked flame. United Utilities says it could cause more damage.
- Check for leaks before turning the water back on. Frozen pipes can crack and leak or burst as they thaw.
- Prevent it by lagging pipes and tanks in unheated areas, covering outdoor taps and leaving the heating on low in cold weather.
What causes frozen pipes
Pipes freeze when they are exposed to sub-zero temperatures. Yorkshire Water says to check for pipes, taps, cisterns, tanks and water meters in unheated areas that might be exposed to the cold.[3]Yorkshire Water, Get winter ready Lofts, garages, outbuildings and outdoor taps are the usual places.
Frozen pipes cause two problems. The first is no water, or a weak trickle. The second is damage. Thames Water says a frozen pipe may crack or burst when the temperature rises, and that leaks and bursts can show up as the pipe thaws.[1]Thames Water, Frozen or burst pipes That is why checking afterwards matters.
What you can do yourself
Start by ruling out the obvious. United Utilities says to check whether you have a card about planned work, check for an emergency in your area and ask your neighbours. If you are the only one without water, you may have frozen pipes.[2]United Utilities, Frozen pipes Thames Water says a frozen pipe often has a light coat of frost on the outside, and the water from your taps may slow to a trickle.[1]Thames Water, Frozen or burst pipes
Then follow these steps, drawn from both companies.[1]Thames Water, Frozen or burst pipes[2]United Utilities, Frozen pipes
| Step | Action |
|---|---|
| 1 | Turn off the stopcock, clockwise. It is usually under the kitchen sink |
| 2 | Open the cold tap, so the water can escape as the pipe thaws |
| 3 | Take off any lagging on the pipe and move things you want to keep dry away |
| 4 | Thaw slowly with a hot water bottle wrapped in a cloth or warm towels |
| 5 | Check the pipe for leaks before turning the water back on |
United Utilities also allows a hairdryer in short bursts if it is safe to do so, keeping well away from water. It warns against a blow torch or any kind of naked flame, as this could cause more damage.[2]United Utilities, Frozen pipes The safest approach is the slow one with towels or a wrapped bottle.
To check for leaks after thawing, Thames Water suggests running a dry cloth along the pipe. If it comes away wet, watch for a few minutes. If water keeps escaping, you probably have a leak and should call a plumber, and leave the water off until the pipe is fixed.[1]Thames Water, Frozen or burst pipes See burst pipe for what to do then.
If your water does not come back on, United Utilities says to check with your home insurance company to see whether you are covered, or call a plumber.[2]United Utilities, Frozen pipes A frozen condensate pipe on a boiler is a separate problem, covered in condensate pipe. HSE says anyone employed to work on gas appliances in domestic premises must be a Gas Safe registered engineer.[4]Health and Safety Executive, Domestic gas: frequently asked questions
How to prevent it
Yorkshire Water gives four simple steps.[3]Yorkshire Water, Get winter ready Cut lagging to size and clip it on to pipes, tanks and cisterns in unheated areas, using cable ties to hold it. Fit tap covers on outdoor taps. If you can, leave the heating on constantly at a low temperature. If severe weather is forecast, set the heating to your usual level, day and night. Finally, find your stop tap before the cold arrives.[3]Yorkshire Water, Get winter ready
Example
Tom in Otley comes down on a freezing January morning to find the kitchen tap barely running. His neighbours have water, so he suspects a frozen pipe. He turns off the stopcock, opens the cold tap, and lays a warm towel on the pipe under the sink. An hour later the water runs again. He wipes along the pipe with a dry cloth and finds no leak. Before the next cold snap he clips lagging onto the pipes in the loft and fits a cover to the outside tap.
What people get wrong
Many people reach for a blow torch to save time. United Utilities warns that a blow torch or any naked flame could cause more damage. Slow, gentle warmth is the safe way, and it is worth taking the time.
The second mistake is to turn the water back on without checking. Pipes may leak or burst as they thaw, so the check along the pipe matters as much as the thaw itself.[1]Thames Water, Frozen or burst pipes
The bottom line
A frozen pipe shows as frost and a slow or absent water flow. Turn off the stopcock, open a cold tap and thaw gently with a wrapped hot water bottle or warm towels. Never use a naked flame. Check for leaks before turning the water back on. Lag exposed pipes and keep the heating on low in cold spells, and know where your stopcock is.
Common questions
How do I know if my pipes are frozen?
Thames Water says a frozen pipe often has a light coat of frost on the outside, and the water from taps may slow to a trickle. United Utilities says to check first that the water is not off for planned work, and to ask your neighbours.
How do I thaw a frozen pipe safely?
Turn off the stopcock and open a cold tap. Then thaw the pipe slowly with a hot water bottle wrapped in a cloth or warm towels. Do not use a blow torch or any naked flame, because United Utilities says it could cause more damage.
What if the pipe has burst?
Keep the stopcock off, turn off the heating, open the taps to drain the system and soak up the water. If water is near electrics, switch them off at the mains. Call a plumber and check your insurance.
Is it worth leaving the heating on?
Yorkshire Water advises leaving the heating on constantly at a low temperature so pipes do not freeze. If severe weather is forecast, set it to your usual level day and night.
Sources
We cite the original source for every figure: government, regulators, standards bodies and manufacturers' own documents. Each one shows the date we last checked it.
- Thames Water. Frozen or burst pipes. Checked 11 November 2026. ↩
- United Utilities. Frozen pipes. Checked 11 November 2026. ↩
- Yorkshire Water. Get winter ready. Checked 11 November 2026. ↩
- Health and Safety Executive. Domestic gas: frequently asked questions. Checked 11 November 2026. ↩