When a pipe bursts, the first move is to shut off the water at the internal stopcock — the valve that controls the mains supply into your home — then open the cold taps to drain the system and call a plumber. Everything else, from mopping up to switching off the electrics, comes after the flow has been stopped.
The first steps when a pipe gives way
Stop the water before you do anything else. Turn the internal stopcock clockwise until it closes, which cuts off the mains supply feeding your pipes. If the leak continues, the water already sitting in the system needs to drain away.
Open every cold tap in the house and flush the toilets to empty the pipework. Leave hot taps until last, and switch off the boiler or immersion heater first so you do not run a hot system dry.
If water is near light fittings, sockets or the consumer unit (the fuse box), turn off the electricity at the mains before you wade in. Water and electricity together are dangerous, and a burst pipe in a ceiling can soak wiring you cannot see.
Finding and using your stopcock
Everything else, from mopping up to switching off the electrics, comes after the flow has been stopped.
The internal stopcock is usually under the kitchen sink, but it may also sit in a utility room, a downstairs cloakroom, under the stairs or near the front door. In older homes it can be tucked behind a cupboard or below floorboards. It is worth locating it now, while there is no emergency, rather than hunting for it with water pouring through a ceiling.
To close it, turn the handle clockwise. If it has not been moved in years it can be stiff or seized — gentle, steady pressure usually works better than force, and a plumber can replace a valve that no longer turns. A few homes also have an external stopcock at the boundary, often under a small metal cover in the pavement or driveway, which the water company can access.
Once a year, give the stopcock a quarter turn and back again to keep it from sticking. That small habit can save a great deal of trouble when seconds matter.
Why pipes freeze and split
Pipes burst in cold weather because water expands as it freezes. A frozen plug of ice blocks the pipe and pushes against the walls and joints; the split often appears once the ice thaws and water flows again, which is why a leak can show up hours after the freeze.
The most vulnerable pipes are those in unheated spaces — lofts, garages, outbuildings, and runs against external walls. Pipes that are exposed or poorly lagged (insulated) freeze first.
A few measures reduce the risk during a cold snap:
- Lag exposed pipes and water tanks with foam insulation, especially in the loft and garage.
- Keep the heating ticking over at a low temperature when the house is empty in freezing weather.
- Fix any dripping taps, since a slow drip can freeze and block the outflow.
- Know where the stopcock is, so you can act quickly if a thawed pipe starts to leak.
If a pipe freezes but has not yet split, turning off the supply and gently warming the frozen section — with a hot water bottle or a hairdryer on a low setting — can ease the blockage. Never use a naked flame, and never apply sudden heat, as that can crack the pipe.
Holding back the damage until help arrives
After the water is off, the priority is limiting how far it spreads. Move furniture, electricals and anything valuable clear of the wet area, and lift rugs and curtains off soaked floors.
Place buckets or bowls under an active drip and put towels down to soak up standing water. If water is pooling in a ceiling and the plaster is bulging, it may be safer to pierce a small hole at the lowest point to let it drain into a bucket in a controlled way, rather than letting the whole ceiling come down at once. That is a judgement call, and only worth attempting if you can do it safely.
Take photographs of the damage before you clear up — these are useful if you make a home insurance claim. Most buildings and contents policies cover sudden escapes of water, though the cause and any maintenance issues can affect what is paid out, so it is worth reading the policy or speaking to the insurer.
What an emergency call-out involves
An emergency plumber aims to stop the leak and make the situation safe, rather than carry out a full, permanent repair on the first visit. A typical call-out starts with isolating the affected section, draining it and identifying the burst or failed joint.
The plumber may fit a temporary repair — a compression coupling or a pipe clamp — to get the water back on, then return to replace the damaged section properly once it has dried out. For a frozen pipe, they will thaw and inspect it for cracks before restoring the supply.
When arranging a visit, it is reasonable to ask a few things up front:
- Whether there is a call-out charge and how labour is billed, particularly outside normal hours.
- How quickly someone can attend, and what to do in the meantime.
- Whether the plumber is registered with a recognised trade body and is insured.
- Whether the work comes with any guarantee.
While you wait, keep the stopcock closed and the taps open if the leak is ongoing. A clear account of where the water is coming from, and the fact that the supply is already off, helps whoever attends get to the problem faster.