Where is the water actually coming from?

Water rarely shows itself at the point where it escapes. It runs along the top of a ceiling, follows a joist or a pipe, and comes through at the lowest point it can find, which may be a room or two away from the fault. A patch on the hall ceiling can come from a bath waste in the room above, from a radiator pipe on the landing, or from rain getting past a roof tile.

Before you assume plumbing, note when the mark grows. If it only spreads after heavy rain, the roof, the gutters or a window are more likely than a pipe. If it spreads after someone has used the bath, basin or washing machine, suspect the waste pipes and the seals around that fitting. If it keeps growing whatever anyone is doing, a pressurised pipe on the cold, hot or heating side is the usual culprit.

How do I limit the damage while I wait?

Close the stopcock if the water keeps coming, and open a cold tap on the lowest floor so the pipes drain down
Switch off the boiler and any immersion heater once the water is off
Keep clear of light fittings and sockets below the wet area, and leave a dripping ceiling rose alone
Put a bucket under the drip and pierce a bulging patch of plasterboard with a screwdriver so the water drains in a controlled way, rather than bringing the ceiling down
Move furniture, rugs and electrical items away from the wet area and lift any carpet you can

Photograph the damage as it develops. A plumber, a loss adjuster and a decorator will all want to see it.

Which pipe is mine and which is the water company's?

In England the water company owns the pipe from the main in the street as far as the boundary of your property, usually to a stop tap near the pavement. From the boundary into the house the supply pipe is normally the owner's. So a wet patch in the front garden that never dries, or water trickling along the drive, is likely to be a job for a plumber, while water rising through the road or pavement is one to report to your water company.

Where several houses share one supply pipe, as in some Victorian terraces around New Barnet and East Finchley, the owners served by it usually share responsibility for it too.

What happens in a flat?

Water from the flat above is a frequent complaint in converted houses and blocks. The lease sets out which pipes belong to each flat and which are the freeholder's, and whoever owns the pipe that failed is responsible for repairing it. Who pays for the damage below depends on the lease, the building's insurance and whether anyone was careless. Tell the people upstairs and the managing agent or freeholder as soon as you see water, keep a note of dates and photographs, and only then start arranging the repair to your own side.

The plumber can usually say which way the water is travelling, but may need access to the flat above to prove it.

Will the plumber dry the house out as well?

No. The plumber stops the water and repairs or replaces the failed pipe, joint or fitting. Drying a floor or wall, replacing plasterboard, relaying flooring and redecorating are separate trades, and wet timber and plaster need weeks rather than days before anything is put back.

If you expect to claim on your buildings or contents insurance, speak to the insurer before any repair goes ahead. Many policies include cover for finding the leak and opening up the building to reach it, often called trace and access, but the wording differs between insurers and some pay for the damage but not for the repair of the pipe itself.

Why do older houses leak more?

Much of the borough's housing dates from the Edwardian years and the 1930s. Pipework from those decades has been altered many times, with lead, iron, copper and plastic joined together as kitchens and bathrooms moved around the house. Joints between different materials, pipes rubbing where they pass through joists, and compression fittings hidden behind boxing are all common sources of slow drips. A plumber can tell you whether a repair is enough or whether a longer run should be renewed.

What belongs in the enquiry?

your postcode, which decides whether a plumber can be found at all
where the water is showing and when it gets worse
whether you have found and closed the stopcock
whether the home is a house, a converted flat or a purpose-built block
any sign that the water comes from a neighbour
whether an insurer is already involved

Who you will hear from

We pass your enquiry to one local plumber, if one covers your postcode. It is never sent to a list of companies. If nobody covers your postcode, we will tell you and will not pass your details on.