What should you do if a pipe bursts? Act in this order:
- Turn off the inside stop tap (clockwise) to cut the mains water feeding the burst.
- Switch off the boiler or immersion heater, then open every tap and flush the toilets so the pipework empties through the taps instead of through the hole.
- Keep away from wet electrics. If water has reached sockets, lights or the fuse board, do not touch them; switch the electrics off at the fuse box only if it is dry and you can reach it safely.
- Catch and contain. Put buckets under drips, move what you can, and lift sodden rugs; if a ceiling below is bulging with trapped water, stand clear of it.
- Call an emergency plumber, and photograph the damage for your insurer before you start mopping up.
In a 2021 WaterSafe survey of 2,000 UK homeowners, 53% did not know what to do if a pipe burst in cold weather, and even among those who did know, only 2% mentioned draining the system. Those first two steps matter most: the stop tap halts new water coming in, and opening the taps clears what is already in the pipes, which is often several litres poised directly over your ceiling. The rest of this guide covers finding that stop tap before you ever need it, why pipes burst in the first place, what a repair costs, and whose job the pipe is when the burst is outside the house.
Know your stop tap before you need it
Hunting for the stop tap mid-leak is pure damage; finding it today costs nothing. Trace the cold pipe that feeds your kitchen tap back towards where it enters the building and you will usually run straight into it: a brass valve on the incoming main, most often in the cupboard under the kitchen sink. If it is not there, the other regular spots are an under-stairs cupboard, a downstairs WC, a utility room, a garage, or boxed in at floor level just inside the hall in older houses.
Once found, do three things. Label it, so anyone in the house can shut the water off without you. Test it when the clocks change, twice a year, by closing it fully and reopening it a quarter-turn back from fully open, which keeps it from sticking. And never lean hard on a stiff one in a crisis; a spindle forced past its limit can break off and leave you with no valve at all. If yours is seized, you can still shut the whole supply at the external stop valve at the property boundary, beneath a small hinged plate set into the pavement or drive; turning it usually needs a long-handled stop tap key from any DIY shop.
One caveat worth knowing in advance: shutting the stop tap stops the mains, but water already stored in a loft tank or hot water cylinder can keep feeding some pipes until it empties. That is exactly why step two is to open the taps and drain everything down.
Why pipes burst
Freezing. Water expands by nearly 10% when it turns to ice, which is enough to split copper and plastic alike, and even brand-new pipework is not exempt. The cruel part is the timing: the split often stays hidden while the ice plugs its own hole, and the flood arrives with the thaw. Thames Water’s guidance makes the same point, advising householders to check lofts and garages for drips as soon as the weather warms. Pipes in unheated spaces and along exterior walls freeze first.
A drill or nail. Plenty of bursts are self-inflicted: a screw driven into a stud wall, a nail through a floorboard, a shelf bracket that found a hot water pipe. Sometimes the jet is instant; sometimes the fixing seals its own hole for months and the leak begins when it rusts.
Age. Pipework wears out. Decades-old copper develops pinholes, old fittings and compression joints loosen as buildings move, and corroded steel or lead supply pipes from earlier eras can fail suddenly rather than gradually.
Pressure. Surges in mains pressure, water hammer from fast-closing valves, and a failed pressure-reducing valve all stress pipework beyond what it was fitted for, and the weakest joint pays the price.
The freeze-season checklist
December to February is burst season, and almost everything on the official prevention lists is cheap. Drawing on the Met Office’s winter home advice and water companies’ own guidance:
- Lag the vulnerable runs. Foam pipe insulation costs a few pounds a metre. Prioritise the loft, the garage, outbuildings, and any pipe on an outside wall, and close the gaps at bends and valves where cold air gets in.
- Leave the heating on low when you are away. A few degrees of background warmth through a cold snap is far cheaper than a ceiling down. For a long winter absence, go further: turn off the stop tap and drain the system so there is nothing left to freeze.
- Deal with outside taps. A garden tap and its feed pipe are the most exposed plumbing you own. If there is an isolation valve indoors, close it for the winter and open the outside tap to empty the run; an insulated cover helps where there is no valve.
- Ignore the dripping-tap advice. Leaving taps trickling overnight is North American guidance written for different plumbing and different winters. No major UK authority recommends it; the UK-appropriate versions are insulation, background heat and, for empty properties, draining down.
- If a pipe does freeze, thaw it gently. Shut the stop tap, open the nearest cold tap, and warm the pipe slowly with a hot water bottle or towels soaked in warm water. Never use a naked flame or blowtorch, which the Met Office warns can damage the pipe and start a fire.
Inside or outside: whose pipe is it?
A burst inside the house is always the owner’s to fix (in rented homes, the landlord’s). Underground, the split follows the boundary: the Consumer Council for Water explains that the water company owns the main in the street, the connection up to your property boundary and the external stop valve, while the buried supply pipe from the boundary into your home belongs to you, and a pipe serving several properties is the joint responsibility of everyone connected to it. Two practical notes: a leak in the road or pavement should be reported to your water company rather than a plumber, and if you suspect your own supply pipe, it is still worth asking the company first, since many offer one-off help or subsidised repairs on private supply pipes.
What a burst pipe repair costs in the UK
Market figures first. Fantastic Services’ 2026 price guide puts most leaking and burst pipe repairs at £80 to £250 across the UK, rising to £120 to £350 in London and the South East. Within that, an accessible pipe repair typically lands around £100 to £150, while a pipe behind a wall or under a floor can run from £150 to £250 or more because of the opening-up involved, with making good charged separately. Out-of-hours work often runs 1.5 to 2 times the standard rate plus a call-out fee, which is why a published emergency price is worth checking before you ring anyone.
TrueFlow’s emergency call-outs start from £120 including VAT. The line is staffed every day of the year, around the clock, and we aim to reach genuine emergencies within 60 minutes of the call. The exact price is agreed with you before any work starts, so the figure you approve at 3am is the figure you pay, and every repair carries a 6-month guarantee. Published prices are on the pricing page, and the emergency plumbing service covers burst pipes, major leaks and failed stop taps across Berkshire, including emergency plumbing in Bracknell itself.
Insurance, briefly
Buildings insurance generally covers the damage a sudden burst causes, listed in most policy wordings as “escape of water”, though the few pounds of pipe and fitting are often excluded while the ruined ceiling and flooring are covered. Your part is evidence and speed: take photos of every affected room before you clean up, keep receipts for emergency work, and notify the insurer promptly. The claims process itself, including what evidence insurers expect and when a claim costs more than it returns, is covered in our guide to drain repairs and home insurance; the same principles apply to water claims.
When the burst is hidden
Not every burst makes a puddle. If the boiler needs repressurising every few days, the meter registers use while the house sleeps, or a damp patch keeps growing with no obvious source, you may have a concealed failure rather than a visible one. That is a different problem with a different method, covered step by step in our guide to telling whether you have a water leak. Professional leak detection then pinpoints the fault with listening equipment, thermal imaging and tracer gas, so nothing is opened on spec; quotes for detection are free, with the exact price agreed before work begins.
Burst pipe FAQs
Can a small burst pipe wait until morning?
Only if you can fully isolate it and it stays isolated. With the stop tap closed and the system drained, a minor split on an accessible pipe can usually wait for a daytime visit. If you cannot stop the flow, if water is anywhere near electrics, or if it is coming through a ceiling, treat it as an emergency and call immediately.
Does turning off the stop tap stop every leak?
No. The stop tap only cuts the incoming mains, so a loft tank or hot water cylinder can keep feeding the burst until it empties, which is why you should open all taps and flush toilets to drain the system. A leak on the central heating circuit will not stop at the stop tap either: a sealed system holds its own water, and an older open-vented system keeps feeding from the small tank in the loft until that empties. Either way, switch the boiler off and drain the circuit instead.
How long does a burst pipe repair take?
It depends on access. A split on an exposed pipe is routinely cut out and repaired in a single visit, often within the hour once the engineer is on site. A burst buried in a wall, floor or underground supply run takes longer because the pipe must be reached before it can be fixed, and a firm timescale comes with the diagnosis.
Will home insurance pay for a burst pipe?
Usually it pays for the damage the water caused rather than the pipe repair itself; see our home insurance guide for how claims work and when claiming is worthwhile.
If water is escaping right now
Shut the stop tap, open the taps, stay clear of wet electrics, and then ring 0808 175 7440. TrueFlow answers 24 hours a day, 365 days a year, aims to reach genuine emergencies within 60 minutes, and agrees your exact price before any work starts.