Burst pipe at home: what to do in the first five minutes

A pipe does not need to split wide open to do serious harm. A pinhole in a copper run under the bathroom floor can soak a ceiling in the time it takes to find a torch, and a pushed-off fitting on a mains-fed pipe can flood a kitchen in minutes. What decides the size of the bill afterwards is mostly what happens before the plumber gets there.

The short version: close the stopcock, open the cold taps to empty the pipes, switch off any electrics the water could reach, catch and soak up what you can, then call or WhatsApp a photo to 07861 933265.

1. Stop the supply

Thames Water’s advice starts in the same place: find the stop tap, which is usually under the kitchen sink, and turn it clockwise until it stops. In London homes it can also hide in less obvious spots:

• Victorian and Edwardian terraces: under the stairs, in the cellar, or under a floorboard by the front door where the supply pipe comes in.
• Purpose-built flats and mansion blocks: in the kitchen, a hall cupboard, beside the hot water cylinder, or on a valve in the communal riser on your landing.
• Conversions: sometimes in the ground-floor flat or the shared hallway, controlling more than one home.

If it is stiff, grip it with a cloth and use steady pressure. Do not lean on it with a wrench; an old valve can snap at the spindle and leave the water running. If the indoor stopcock will not move, the outside stop tap under the small cover in the pavement or front path is the next option, but you will need a key for it.

2. Drain what is left in the pipes

Closing the stopcock stops new water coming in, but the pipes are still full. Open the cold taps around the house, starting with the lowest, and flush the toilets once. This takes the pressure off the split and empties the pipework faster.

Many older London houses still have a cold water tank in the loft feeding the bathroom. Those pipes keep running after the mains is off, until the tank is empty. Running the bath cold tap is the quickest way to drain it. If you can safely reach the loft, there may be a valve on the pipe coming out of the tank that you can close as well.

3. Make the electrics safe

Water travels along joists and cables and very often comes out through a light fitting. Do not use switches or touch sockets in the wet area. If water is anywhere near the electrics, Thames Water’s guidance is to switch them off at the mains; do that at the consumer unit only if you can reach it from somewhere completely dry. If the consumer unit itself is wet, leave it alone and say so when you call.

4. Limit the damage

• Put buckets or bowls under drips, towels along skirting boards and across doorways.
• Lift rugs, move electrical items, books and anything that wicks water out of the room.
• If a ceiling is sagging, keep everybody out from under it.
• Take photos and a short video before anything is moved. Your insurer will want them.

If you live in a flat, tell the neighbour below straight away, and the managing agent if the building has one. If the water is coming from the flat above rather than your own pipes, our guide to a leak from the flat above walks through what to do instead.

What not to do

• Do not wrap tape round the split and turn the water back on “just for an hour”. Pressure finds the weak spot again within minutes.
• Do not pull up flooring or cut into a ceiling to find the leak.
• Do not use a hairdryer or heater near standing water.
• Do not stand on a wet floor and reach for the consumer unit.

Why pipes burst in London homes

Freezing still causes some bursts, usually showing up as the pipe thaws, in lofts, under-floor voids and garages. Many more come from age: copper that has thinned from years of hard water, compression joints that have slowly loosened, push-fit fittings that were never fully seated, and flexible tap connectors behind kitchen units that perish without anyone seeing them. Pipework squeezed into the floors of converted terraces is especially prone, because it often runs through notches in joists and gets knocked during later building work.

When we arrive

Send a photo or short video on WhatsApp to 07861 933265 as soon as the water is off; it tells us what fittings to have ready. We aim to be with you within 60 minutes. The engineer confirms the supply is isolated, finds the failed length or joint, cuts it out and replaces it, then turns the water back on slowly and checks every joint under pressure. If the leak is hidden in a wall or floor, tracing it comes first, so the minimum is opened up. You get a written note of what failed and what was replaced, which is what insurers usually ask for.

The burst pipe repair page has more on the repair, and if the water has already come through a ceiling, see our page on ceiling leaks.

Be ready before it happens

Find your stopcock today, turn it off and on once so you know it moves, and tag it so anyone in the house can find it. Find out whether your bathroom is fed from a loft tank. Save 07861 933265 in your phone. Five minutes now saves a great deal of mopping later.