Two types of people tend to land on this page. One’s getting ahead of a cold snap and wants to know what to check before the weather turns. The other’s standing in a hallway watching water come through the ceiling. If that’s you, skip down to “What to do if a pipe bursts” and call us, everything else can wait.
Why pipes freeze and burst
Water expands when it freezes, and a pipe doesn’t have anywhere to put that extra volume. The pressure builds until something gives, usually at a joint or a thin spot in the pipe. What catches a lot of people out is that the burst rarely happens while the pipe is still frozen solid. It’s when things start to thaw, and the water trapped behind the ice is still under pressure, that the split actually appears. So a burst can seem to come out of nowhere on a milder morning after a hard frost, days after the cold snap that caused it.
The pipes most at risk are the ones in places you don’t heat. This includes lofts, garages, under floorboards near an outside wall, anywhere close to an outdoor tap. We see a lot of this in older properties around Merthyr Tydfil and up through the valleys, where the pipework’s often original and running through parts of the house that never really get warm.
Prevention: lagging, thermostat settings, outdoor taps
A few things done properly before the cold hits will save you a lot of grief.
Lag any exposed pipework. The foam sleeves you can pick up from a DIY shop cost next to nothing and take an afternoon to fit round loft and garage pipes. It’s a small job with a disproportionately good return.
Leave your heating on low overnight rather than switching it off completely. Even a thermostat set to kick in briefly at 12 or 13 degrees keeps enough warmth moving through the house to stop pipes hitting freezing point. This matters most when you’re away, whether that’s a weekend visiting family in Swansea or a longer trip, because an empty house with the heating fully off overnight is when most of the trouble starts.
Drain and cover outdoor taps. Fit an insulated jacket over any outside tap, and where you can, turn off the isolation valve feeding it and let it run dry. Outdoor taps and the short run of pipe just behind them tend to be the first casualty of a cold spell.
And find out where your stopcock is now, not later. More on that below, but it’s the one thing worth checking before you actually need it.
What to do if a pipe freezes
If a tap’s running slow, or not running at all, but nothing’s actually split yet, there’s usually something you can do yourself before it becomes a bigger problem.
Turn off the supply to that pipe if you’re able to, and open the tap so there’s somewhere for the water to go as the ice clears. Warm the frozen section gently with a hot water bottle, warm towels, or a hairdryer on a low setting kept moving, working from the tap end back towards the blockage. Don’t go anywhere near it with a naked flame or a heat gun. Beyond the obvious fire risk, that kind of heat can damage the pipe and turn a frozen one into a burst one.
Can’t find where it’s frozen, or it’s somewhere you can’t get to safely? Leave it to us rather than pulling up floorboards yourself.
What to do if a pipe bursts
Move quickly here. If water’s actively coming through, do this in order:
- Turn off the stopcock straight away. Most commonly it’s under the kitchen sink, though in older houses it can turn up near the front door, in an airing cupboard, or occasionally out in an external meter box. If you’re not sure where yours is, check today rather than while you’re stood in an inch of water trying to find it.
- Switch off electrics near the leak. Water and electrics don’t go together, so if the leak’s anywhere close to sockets, switches or light fittings, cut the relevant circuit at the fuse board if you can reach it safely.
- Open the nearest taps to drain what’s left in the system and take the pressure off.
- Call us. Once the water’s off and it’s safe, get in touch on our 24/7 emergency callout and we’ll have someone on the way.
When to call an emergency plumber
Plenty of plumbing problems are fine to sit with for a day or two. A slow drip, a leaky washer, a tap that’s seen better days. A burst pipe isn’t one of them. If water’s actively escaping, if you can’t get to the stopcock, or there’s any smell of gas around the leak, stop and call us rather than trying to sort it yourself. We cover emergency callouts right across South Wales, from Cardiff and Newport out to Pontypridd and the valleys, and we’re Gas Safe registered and hold the relevant industry accreditations, so whoever turns up at your door knows exactly what they’re dealing with. For anything less urgent, have a look at our plumbing services page for the full picture of what we cover.
Frequently Asked Questions
Where is my stopcock, and why does it matter?
It’s the valve that shuts off your water supply to the whole house, most often found under the kitchen sink but sometimes elsewhere in older properties. Knowing where it is before you need it means you can stop a leak in seconds instead of searching for it while the water keeps coming.
Can I use a hairdryer to thaw a frozen pipe?
You can, on a low setting, but ensure that you keep moving, working from the tap end towards the blockage. Just steer clear of naked flames or heat guns directly on the pipe. Both are a fire risk and can damage the pipe itself.
How much does an emergency callout cost?
It depends on the time of day, what’s actually wrong, and how long the job takes to sort, so we’d rather give you a proper figure when you call than a vague number here. We’ll always be upfront about cost before any work starts.
Does home insurance cover burst pipe damage?
Most standard home insurance covers burst pipe damage, though the terms differ between insurers, and some expect you to have taken reasonable precautions, like keeping the heating on while you’re away. It’s worth checking your own policy rather than assuming, and we’re happy to put together a report for insurance purposes if you need one.
Don’t wait until it’s an emergency
Reading this ahead of winter? A bit of lagging and a quick thermostat check now could save you a far more stressful call later. Reading it mid-leak? Stop here and call our 24/7 emergency line. We’re on hand around the clock across South Wales, whatever time it happens to be.