A burst pipe in a London property can cause thousands of pounds of damage in minutes. Here is what to do immediately, where to find your stop cock and how to minimise damage while you wait for an emergency plumber.
A burst pipe is one of the most stressful plumbing emergencies a London homeowner or landlord can face. Water escaping at mains pressure can flood a room in under an hour and cause serious structural damage to plaster, timber flooring and the electrics below. Knowing what to do in the first few minutes significantly limits the damage.
Step 1: Turn off the water supply
The first priority is to stop the flow of water. The internal stop cock is usually located under the kitchen sink. Turn it clockwise to close it. This should stop the flow from internal supply pipework. If you cannot locate the internal stop cock, the external stop cock is in the pavement outside the property — it requires a stop cock key to operate, but Thames Water can attend for emergencies.
Step 2: Turn off the electrics if necessary
If water is running near electrical outlets, light fittings or the consumer unit (fuse board), turn off the electricity at the main switch before touching any electrical equipment. Do not use electrical items in rooms where water has entered. Water and electricity are a life-threatening combination.
Step 3: Drain the system
With the stop cock closed, open all cold water taps to drain down the residual water in the pipework. This reduces the pressure behind the burst and limits further escape. If the burst is in a hot water system or central heating pipe, the system will need to be drained separately — your boiler manual or an emergency plumber can advise.
Step 4: Contain and document the damage
Use towels, bowls and buckets to contain water while you wait for an emergency plumber. Take photographs of the damage for your insurance claim. Note which room the burst is in, where water has spread and any visible damage to ceilings or floors. The more detailed your documentation, the stronger your insurance claim.
Step 5: Call an emergency plumber
Once the water is off, call an emergency plumber. Explain the location of the burst, whether you have successfully closed the stop cock and what visible damage has occurred. A well-organised emergency plumber will give you an estimated attendance time and confirm the hourly rate before attending.
Common causes of burst pipes in London
London's older housing stock is particularly vulnerable to burst pipes during cold snaps. Pipes in uninsulated loft spaces, exterior walls and below ground-floor void spaces are most at risk of freezing and bursting. Poorly supported pipework that vibrates in older buildings, and lead or iron pipework in pre-war properties, are also common failure points.
Frequently asked questions
Where is the stop cock in a London flat?
In most London flats, the internal stop cock is under the kitchen sink. In some older buildings it may be in the hallway or near the front door. If you cannot find it, contact your building management or Thames Water.
What should I do if water is coming through my ceiling?
This indicates a leak from the property above. Turn off your electricity if water is near electrics, contain the water with buckets, then contact the property above or your building management immediately. For a rented flat, call your landlord or managing agent.
Will my insurance cover a burst pipe in London?
Most buildings insurance policies cover sudden escape of water from burst pipes. Document the damage immediately with photographs and report to your insurer as soon as possible. Ongoing or slow leaks may be treated differently.
How much does an emergency plumber cost in London?
Emergency plumber rates in London vary significantly. Expect hourly labour rates of £80–£150 per hour during normal hours, with premium rates for evenings, weekends and bank holidays. Always confirm the rate before authorising attendance.