What to Do in a Water Leak Emergency in Your London Home
A burst pipe or sudden water leak can cause thousands of pounds of damage within hours. Knowing what to do in the first 10 minutes limits the damage significantly.
Immediate Steps
- Turn off the mains water supply — the stopcock is usually under the kitchen sink, in a cupboard or near the water meter. Turn it clockwise to close
- Turn off the central heating — if the leak is in a heating pipe, turn off the boiler and allow the system to cool
- Turn off electricity in affected areas — water and electricity are dangerous together. Use the consumer unit to isolate circuits near the leak
- Open all taps to drain residual water from the pipes
- Contain the leak — use towels, buckets and plastic sheeting to protect flooring and furniture
- Document the damage — take photos and videos for your insurance claim before cleaning up
- Call a plumber — for a burst pipe you need an emergency plumber as soon as possible
Where to Find the Stopcock
Common locations for the internal stopcock:
- Under the kitchen sink
- In an airing cupboard
- Under the stairs
- In a bathroom cupboard or under the bath panel
- Near the front door at floor level
If you cannot find the internal stopcock, Thames Water (or your regional supplier) has an external stopcock near the property boundary. You will need a stopcock key to operate this.
Calling Your Insurer
Report the leak to your buildings insurer as soon as it is safe to do so — most policies have a 24-hour claims line. Insurers prefer you report promptly. Keep all receipts for emergency work and temporary repairs.
Drying Out
After a significant water leak, structural drying is often needed. Insurers typically arrange this. Do not decorate over damp walls — moisture meters can reveal hidden damp that looks dry to the eye.
Frequently asked questions
Where is the main water stopcock in a London terraced house?
Most commonly under the kitchen sink. If not there, check under the stairs, in a bathroom cupboard or near the front door at skirting board level.
How do I turn off the stopcock if it is stuck?
Old stopcocks can seize up. Apply penetrating oil (WD-40) and allow it to soak. Grip the spindle with pliers and apply gentle pressure — do not force it hard as the valve can break. Have Thames Water's external supply stopcock as a backup.
Should I turn off the electricity if there is a water leak?
Yes — if there is any risk of water reaching electrical fittings, isolate the affected circuits at the consumer unit. Never touch electrical fittings or switches with wet hands.
How much does an emergency plumber cost in London?
Emergency callout rates in London typically range from £80–£150 for an out-of-hours call, plus labour and parts. Rates vary significantly between companies. Check the call-out charge before booking.