A boiler leaking water in the middle of a London winter is more than an inconvenience. Left alone, a small drip can soak through ceilings, reach electrical fittings and leave your home without heating overnight.

Need help now? Call 07380 557898. A Gas Safe engineer can be with you within the hour, 24/7, with no call-out fee.

First: can you smell gas?

If you smell gas, stop reading and act immediately:

Do not touch light switches, plugs or anything that could spark.
Open doors and windows.
Turn off the gas at the meter if it is safe to do so.
Leave the property and call the National Gas Emergency Service on 0800 111 999.

A water leak is urgent. A gas leak is an emergency. Once the gas network has made it safe, call us on 07380 557898 to repair the boiler.

5 steps to take while you wait for an engineer

1. Switch the boiler off

Turn the boiler off at its control panel, then at the fused spur (the wall switch next to it). This stops the pump pushing more water through the leak.

2. Shut off the water supply

Find your stopcock, usually under the kitchen sink, and turn it clockwise until it stops. If the boiler has its own cold-water isolation valve underneath, close that too.

3. Keep water away from electrics

Do not touch sockets, switches or the boiler’s wiring if they are wet. If water is reaching electrical fittings, switch off the power at the consumer unit, but only if you can reach it with dry hands from a dry floor.

4. Contain the damage

Put a bowl or towels under the drip and move valuables out of the way. Take photos of the leak and any damage: your insurer will ask for them.

5. Do not open the boiler casing

Under UK law, only a Gas Safe registered engineer may work on a gas appliance. Opening the case yourself is dangerous and can void both your warranty and your home insurance.

Why boilers leak more in winter

Pressure relief valve. When pressure climbs too high, the valve discharges water. Frequent drips usually point to a faulty valve or a failing expansion vessel.
Corroded pipes and joints. Cold snaps make metal contract, which exposes weak joints that held up all summer.
Pump seal failure. Boilers run hardest in winter, and worn pump seals are a common source of water under the unit.
Frozen condensate pipe. Strictly speaking this isn’t a leak, but it is the number one winter call-out. The boiler locks out and often shows a fault code. Pouring warm (never boiling) water along the outside section of the pipe can thaw it.

When to call an emergency engineer

Call straight away if:

water keeps coming after you have isolated the boiler,
the pressure gauge keeps dropping below 1 bar,
the leak is near electrics or coming through a ceiling,
you have no heating or hot water and vulnerable people in the home.

Our Gas Safe engineers cover every London borough, day and night. Call 07380 557898 now and tell us what you’re seeing. We’ll diagnose it on the phone and dispatch the right engineer.