What To Do If You Have a Water Leak

Immediate steps to limit damage from a leak, how to find and use your stopcock, and when it becomes an emergency.

Last updated: 2026-10-19

The first priority with any leak is to stop the water and protect people and property. Most damage happens in the first few minutes, so knowing where your stopcock is matters more than anything else.

Immediate steps

1. Turn off the water. Use the nearest isolation valve, or the main stopcock.
2. Turn off the electrics to affected areas if it is safe to reach the consumer unit without touching water. If you cannot do this safely, leave it.
3. Contain the water. Buckets, towels, and a bowl under the drip.
4. Move valuables and furniture away from the leak.
5. Call a plumber — describe the location and whether the water is still running.

Finding your stopcock

The main stopcock is usually:

• under the kitchen sink
• in a downstairs cupboard or utility room
• where the water supply enters the property, often near the front boundary
• in some flats, in a communal cupboard

It is usually a brass tap that turns clockwise to close. Turn it gently but firmly. If it is stiff, do not force it until it breaks — but if water is pouring, close it as best you can.

Many homes also have isolation valves on individual appliances and radiators, which let you stop water locally without shutting off the whole house.

Leaks you can often contain yourself

• A dripping tap — usually a washer or cartridge, and rarely urgent
• A leaking radiator valve — isolation valves may let you stop flow to that radiator
• A leaking toilet inlet — the isolation valve behind the toilet often stops it

When it is an emergency

Call urgently if:

• water is coming through a ceiling, or near electrics
• the leak cannot be stopped with the stopcock
• there is sewage backing up
• you have no water at all
• a pipe has burst

See our emergency plumber page for how to reach us fastest. Call rather than using a form in an emergency.

After the leak is fixed

Ask whether the repair addresses the cause, not just the symptom. A pinhole in a pipe can indicate corrosion elsewhere, and repeated leaks on the same system are worth investigating. If a boiler or heating system lost pressure, it will need refilling and checking — see how to repressurise a boiler.