Water Escaping In The House: What To Do In The First Five Minutes

Turn the water off before you look for the leak

The internal stopcock is the one valve that stops mains water entering the property. It is a brass valve on the incoming pipe, usually with a small round handle, and it closes clockwise. Turn it fully, not most of the way. A partly closed stopcock still feeds a burst pipe at a useful rate and it is a common reason people report that turning the water off did nothing.

Once it is shut, open the cold tap on the kitchen sink and leave it running. That kitchen cold tap is normally the one outlet fed directly off the rising main, so opening it drains the pressure that is still sitting in the pipework and lets the leak slow to a dribble rather than continuing at full flow. If the leak is upstairs, open the taps upstairs too. Water already above the failure point has to go somewhere, and you would rather it went down a plughole than through a ceiling.

What the stopcock does not do is empty a hot water cylinder or a loft tank. Those are stored volumes, and a cylinder in a London house can hold anything from a hundred and fifty to three hundred litres that will keep feeding a leak on the hot side long after the mains is off. If the water is clearly coming from the cylinder or from hot pipework, you need to shut the outlet from the storage as well, which is covered further down.

• Close the internal stopcock fully, clockwise
• Open the kitchen cold tap to drop the pressure in the rising main
• Open hot and cold taps upstairs if the leak is above you
• Only then start looking for where the water is coming from

Where the stopcock actually is

In most London houses it is under the kitchen sink, at the back, behind whatever is stored in that cupboard. That is the first place to look and it is right perhaps three quarters of the time. The pipe it sits on is the one that comes up through the floor and is cold to the touch.

In a flat, especially a conversion, it moves around. Common positions are inside the airing cupboard next to the cylinder, under the bath panel, in the hallway cupboard with the consumer unit, behind a removable panel in a bathroom, or in a riser cupboard on the communal landing that serves several flats. Purpose built blocks often have a valve on the landing labelled with the flat number. Older conversions frequently have the stop tap in the basement or the ground floor flat, which is exactly the problem it sounds like at one in the morning.

There is also an external stop tap, usually under a small metal or plastic cover in the pavement or front path, sitting at the bottom of a narrow vertical chamber. It needs a stopcock key, a long T shaped tool, because it is too deep to reach by hand. This one belongs to the water company and it controls the supply to the property from the street. It is the backup when the internal valve fails, and it is worth knowing where yours is before you need it.

The five minutes to spend on this is not now, it is on a quiet evening. Find the stopcock, turn it off and on once to prove it moves, and put a photograph of its location in your phone. A seized stopcock discovered during a burst is a much worse discovery than a seized stopcock discovered on a Sunday afternoon.

If your first thought was where is my stopcock, you are in the majority, and the answer is usually within a metre of the point where the mains enters the property.

If the stopcock is stiff, do not force it with a wrench while water is escaping. Old brass stop taps snap at the spindle, and a snapped stopcock turns a contained leak into a leak you cannot stop at all. Turn it firmly by hand, and if it will not move, go to the external stop tap in the street instead.

If the stopcock will not close, or there is not one

Work outwards. The external stop tap under the cover outside is the next stage, and a stopcock key from a hardware shop costs very little and lives well in a kitchen drawer. Lift the cover, clear the chamber of leaves and grit, lower the key on to the valve and turn clockwise. It sometimes takes several turns.

Inside, there are usually more valves than people realise. Most modern installations have small isolating valves on the pipe feeding each appliance and each tap, with a slot you turn a quarter turn with a flat screwdriver. When the slot lines up along the pipe the valve is open, and across the pipe it is closed. If you can see that the water is coming from under a basin, a toilet cistern, a washing machine or a dishwasher, an isolating valve a few inches from the failure may be all you need to touch.

In a house with a loft tank, there will normally be a gate valve on the pipe leaving the tank and often a second one on the cold feed to the cylinder. Gate valves have a small wheel head and close clockwise, and they are notorious for seizing because nobody ever turns them. If a gate valve will not budge, tying up the ball valve arm in the loft tank so it cannot refill will at least stop the tank replenishing what is draining out.

• External stop tap in the pavement, turned with a stopcock key
• Quarter turn isolating valves under basins, toilets and appliances
• Gate valves on the outlet of a loft tank or the cold feed to a cylinder
• Tie up the loft tank ball valve if the gate valve is seized

What to do about the electrics when water is coming in

This is the part that is genuinely dangerous and the part most people rush. If water is running down a wall near sockets or switches, dripping through a ceiling on to a light fitting, pooling under a consumer unit, or anywhere near an extension lead on the floor, treat the circuit as live and hazardous until it is off.

Turn the power off at the consumer unit using the main switch, provided you can reach it without standing in water and without reaching through or past running water to get to it. If the consumer unit itself is wet, or the route to it is wet, do not go to it. Leave the property, keep everyone out of the affected rooms, and call your electricity distribution network operator, which in most of London is UK Power Networks, on the national emergency number 105. That call is free and it is the right call.

Do not use a wet vacuum, a dehumidifier or any plugged in equipment in a room where water is still arriving, and do not run a ceiling light to see what you are doing if that ceiling is the one being rained on from above. A bulging, sagging or dripping ceiling is also a physical collapse risk. Get people out from under it rather than standing beneath it with a bucket.

Never touch a consumer unit, socket, switch or light fitting that is wet, and never stand in standing water to reach one. If the electrics are wet or the route to them is wet, leave the area and call 105. Once power has been off in a flooded area, an electrician should check the affected circuits before anything is switched back on.

Is it the cold side, the hot side or the heating?

If the water was hot, the problem is on the stored or heated side, which means the cylinder, the immersion heater boss, the hot pipework or the boiler. Closing the mains stopcock will not empty a cylinder, so look for the valve on the cold feed into the bottom of the cylinder and close that, which stops it refilling as it drains. A cylinder that is leaking from the body itself rather than from a fitting is almost always at the end of its life rather than repairable, and the separate guide to a hot water cylinder leaking covers how to tell a failed fitting from a failed vessel before you spend anything on it.

If clean water is running out of a pipe that discharges outside or into a tundish above the cylinder, that is a safety valve doing its job rather than a burst. It still needs attention, because a valve that discharges is telling you about a pressure or temperature problem behind it, but it is not the same emergency as a failed pipe and it will not usually flood a room. A dripping tundish and a leaking pressure relief valve each have their own short list of causes, and both are worth reading once the immediate mess is under control.

If the water is rusty brown or smells metallic, it is heating system water from a radiator, a valve or a heating pipe rather than fresh mains. Radiator leaks are often at the valve gland or at the union nut and can sometimes be held with a bowl and a towel until an engineer arrives. Central heating water stains fabric and plaster badly, so get something absorbent under it quickly.

If water is coming through a ceiling in a flat and none of your own taps or appliances explain it, the source is very likely the flat above. Knock on the door. Water travels along joists and can surface several metres from the actual failure, so the wet patch in your ceiling is not necessarily under the burst.

• Hot water means cylinder, immersion boss, hot pipework or boiler
• Clear water from a discharge pipe or tundish means a safety valve, not a burst
• Brown or metallic smelling water means a radiator or heating pipework
• Ceiling water in a flat with no local source usually means upstairs

Water coming through a ceiling from the flat above

Ceiling water in a flat is its own problem, because the valve that needs closing is not yours. Your stopcock controls your flat and nothing above it, so shutting it changes nothing if the escape is upstairs. Knock, ring, and if nobody answers contact the building manager, the managing agent or the freeholder, since they can usually gain access or close a riser valve on the landing that serves the whole stack.

While you are waiting, treat the ceiling as the hazard rather than the inconvenience. Turn the power off to that area at the consumer unit if you can reach it safely, move everything out from under the wet patch, and keep people out from beneath it. Water runs along joists and drops at the first gap it finds, so the failure upstairs can be several metres from the stain you are looking at, and a small stain can sit under a very large wet ceiling void.

Record it properly even though the damage is not your fault. Photograph the ceiling, the room and each damaged item, check the date and time on your phone are right, and tell your own insurer as well as the freeholder. Escape of water between flats is usually settled between insurers rather than between neighbours, and the household with dated photographs is the one whose account is accepted.

Water coming through ceiling plaster behaves differently from water running down a wall, because the plaster holds it until it suddenly does not.

• Your own stopcock will not stop a leak in the flat above
• Power off to the affected area before anything else
• Knock upstairs first, then the managing agent or freeholder
• Water travels along joists, so the source may not be above the stain
• Photograph and date everything before you clear anything up

Containing the damage while you wait

Damage from a water escape is done by absorption and by time, not by the volume of water. Lift what you can rather than mopping around it. Rugs, boxes, books, anything electrical on the floor, and the bottom shelf of anything wooden. Put foil or plastic under furniture legs so they do not stain the carpet as the water wicks up them. Move anything irreplaceable out of the room entirely, because it is easier to move it now than to explain the loss later.

For a ceiling that is bulging and holding water, the counterintuitive move is usually the right one. A ceiling that is holding a pool of water will eventually fail all at once and bring plaster down with it, so piercing it deliberately at the lowest point of the bulge with a screwdriver, from the side and not from underneath, with a bucket positioned, is often better than waiting. Do that only if the power to that area is off and only if you can do it without standing under the bulge.

Once the flow has stopped, get air moving. Open windows, open internal doors, and if you have a dehumidifier and the room is safe and dry enough to run one, use it. Plaster and screed hold moisture for weeks, and mould starts to establish in a day or two in a closed warm room.

• Lift soft furnishings, boxes and floor level electricals out of the water first
• Put foil or plastic under furniture feet to stop staining
• Consider draining a bulging ceiling deliberately, from the side, power off, bucket ready
• Ventilate and dry as soon as the flow has stopped

What to photograph for an insurance claim before you clear up

Insurers pay on evidence, and the evidence disappears the moment you start being helpful. Two minutes with a phone before the mopping starts is the highest value thing you will do all day, and people almost never do it because the instinct is to clean.

Photograph wide first so the room and the extent of the water are obvious, then close up on the failure itself if you can see it, then on every damaged item individually. Video is even better than stills for the overall picture because it captures the scale and you can narrate what you are seeing and when. Get the date and time right on your phone, because the metadata is part of what makes the record credible.

Keep what failed. The split section of pipe, the burst flexible tap connector, the failed valve, the perished washing machine hose. An engineer will often cut out a section, and that component is direct evidence of the cause, which is what determines whether a claim is a sudden escape of water, which is normally covered, or gradual failure and poor maintenance, which frequently is not.

Ring your insurer or their emergency line early, before you commission significant drying or strip out work. Most policies want to approve contractors or send their own, and work done without telling them can be argued about afterwards. Emergency work to stop the escape is different and you should never delay that, but keep the invoice and the engineer report for it.

• Wide shots of each affected room before anything is moved or mopped
• Close ups of the failed component and of the water at its highest level
• Individual photographs of every damaged item, including inside cupboards
• Keep the failed part itself, and keep the engineer report and invoice
• Notify the insurer before commissioning drying or strip out work

Do not throw away the failed pipe, hose or valve. It is the single piece of evidence that separates a sudden escape of water from gradual deterioration, and that distinction decides a lot of claims.

What an engineer will do when they arrive

The first job on arrival is to confirm the property is actually isolated, because a partly closed stopcock or a stopcock that no longer seats properly is common enough to check rather than assume. From there it is a question of narrowing down which part of the system is losing water, by isolating sections and watching what happens.

Where the failure is visible, the work is usually cutting out the failed section and replacing it, or replacing the fitting, valve or flexible connector that let go. Where it is not visible, and the water is appearing through a ceiling or a floor with no obvious source, the work becomes leak detection first, using acoustic equipment, thermal imaging or tracer gas to find the failure without opening up half the property speculatively. That is a different visit from a straightforward burst pipe repair, where the failed section is already in front of you and the work is cutting it out and replacing it.

Expect a competent engineer to tell you two things before leaving: what failed and why, and whether anything else in the same system is in similar condition. A failed flexible connector under one basin usually means the others of the same age are worth changing too. That second conversation is the one that stops you doing all of this again in six months.

The hourly rate is fixed and agreed before we attend, and the total depends on how long the job takes and what parts it needs. Emergency work to stop an active escape is normally short. Detection and reinstatement after a hidden leak are longer, and we will tell you which one you are in before starting.

Where the water is escaping inside a wall or under a floor and nothing on the surface explains it, the visit becomes leak detection and repair rather than a straightforward fix, and the tracing work has to come before any pipe is opened up.