If water is coming out of something right now, stop reading and go and find your stopcock. Everything on this page will still be here in five minutes. The single most valuable thing in a plumbing emergency is not the plumber — it is the person in the flat knowing how to turn the water off before anyone arrives.
Once the water is off, the emergency is over and what you have left is a repair. That distinction is the point of this page. Below: what actually counts as an emergency, what you can safely do yourself, how a call-out works, and the particular things about Central London buildings — porters, shared risers, restricted hours, the flat below — that decide how quickly anything can realistically happen.
Turn it off first
Three levels of isolation, in order of preference.
At the appliance. Under a basin, behind a WC, at a washing machine, there is usually a small isolation valve — a chrome fitting with a screwdriver slot. Slot across the pipe means off. If the leak is at one fitting, this stops it and leaves the rest of your flat with water.
At the flat stopcock. Usually under the kitchen sink, in an airing cupboard, or in a service cupboard by the front door. Turn clockwise to close. This kills the flat's cold supply. If you have a hot cylinder it will still have water in it, and a gravity tank will still drain down through open outlets — so also open the taps to drain the system down once the stopcock is closed.
At the building. In a mansion block there is often a communal isolation point, sometimes per riser, sometimes per floor. That is generally not yours to operate — it is the porter's or the managing agent's — because closing it can affect other flats. If you need it, call the porter.
Do this now, while it is dry. Find your stopcock, confirm it turns, and photograph where it is. A seized stopcock discovered at midnight during a burst is a genuinely bad evening, and it is a five-minute problem to prevent.
What is actually an emergency
Being honest about this is in your interest, because it changes what you should do next.
Genuinely urgent. Water you cannot stop. Water reaching a consumer unit, a light fitting, or any electrics. Water going through a floor into another flat. A burst that has already dropped a ceiling. No water at all in an occupied property. Sewage backing up into the flat. A gas smell — which is not a plumbing call at all: leave, and call the national gas emergency line.
Urgent but controllable. A leak you have isolated at a valve. A blocked WC in a flat with a second one. No hot water in mild weather. These need attending to, but they are bookable jobs, not a 2am rescue, and treating them as bookable usually gets you a better outcome and a better price.
Not an emergency, even though it feels like one. A dripping tap, a running overflow into a gully outside, a noisy pipe. Worth fixing — see our guide to dripping tap repair — but nothing is being damaged tonight.
The reason to sort your own call into the right bucket is simple. If it is category one, isolate and get someone out. If it is category two, isolate, breathe, and book it properly with the right parts. Category two jobs done in a panic get temporary fixes that need doing again.
Things not to do
Do not touch electrics that have been wet, and do not switch anything on to see if it works. If water is anywhere near a consumer unit or a light fitting, the correct move is to leave it alone and get an electrician to look before you re-energise. Our electrical page covers that side.
Do not pour drain chemicals into a blocked WC or a blocked sink and then ask someone to work on it. You have now created a hazard for whoever puts their hands in it, and it very rarely works anyway.
Do not take a boiler apart. Only Gas Safe registered engineers may work on gas appliances — that is not a preference, it is the law, and a boiler that is leaking water still has a gas supply in it. Isolate the water and the electric, and leave the appliance to someone registered. Our guide to a boiler not heating water covers what you can and cannot check yourself.
Do not ignore a bulging ceiling. That bulge is holding water and it will let go eventually. Controlled release into a bucket beats an uncontrolled release onto a floor.
The Central London part: why access is the real variable
In a house, an emergency plumber turns up and knocks. In a Central London flat, half a dozen things sit between the call and the repair, and none of them are about plumbing.
Porters and entry. Many mansion blocks in Marylebone, Maida Vale and St John's Wood control contractor access through a porter or a concierge. Sometimes there is a signing-in procedure, sometimes contractors need to be announced by the leaseholder, sometimes there are set hours. If nobody can let a plumber in, nothing else matters. Have your porter's number and your managing agent's out-of-hours number saved somewhere other than in the flat.
Isolation you do not control. If the leak is on a communal riser rather than inside your demise, the valve that stops it may be locked in a cupboard that only the porter or the managing agent's contractor can open. This is one of the most common reasons a burst runs longer than it should — see our guide to a burst pipe in a mansion block.
Where things are. A W1 conversion refitted four times since the 1960s can have pipework, valves and stopcocks in genuinely unpredictable places, none of them recorded. Time on site goes into finding things.
Getting to the street. Parking and loading in W1 and W2 is what it is. Van access, a place to stand, a route to your door — these are real minutes, and pretending otherwise is how people end up making promises they cannot keep.
Working hours. Many blocks restrict noisy work to weekday daytimes. A genuine leak is usually treated differently to planned work, but the rule is your building's, not ours — check with your porter or agent so you know where you stand before you need to.
Why we will not promise you a time
You will see plumbers advertising a fixed arrival window at any hour. We do not, and it is worth explaining why rather than quietly leaving it out.
A promise like that is only honest if the person making it controls the variables. In this part of London they do not. Traffic, the porter, whether the valve is locked, whether the building will let anyone in after hours, and whether the van can stop within a hundred metres of your front door all sit outside anyone's control. A number picked to win the call is a number that gets broken, and you are the one standing in the water when it does.
What we will do is tell you honestly when we can get someone to you, and be straight if the answer is not soon enough — in which case we will say so rather than take the booking and leave you waiting. In the meantime, the isolation steps above are what actually protect your flat, and they work regardless of who eventually attends.
How the call-out actually works
Contact us through the quote form or send a photo on WhatsApp. A photo is worth a lot here: a picture of the leak, the fitting, and the cupboard the stopcock is in tells us what to bring.
Tell us three things. What is wet. Whether you have managed to isolate it. Whether it is going into another flat. That last one changes the priority more than anything else, because a leak crossing a floor is on a clock.
Our plumbing call-out starts from £80. What that covers is attendance and diagnosis: getting to you, finding the cause, and making it safe where we can. If the repair can be done there and then with what is on the van, we will tell you the price for it before we do it. If it needs parts, or if it turns out to be bigger than it looked, you get a fixed quote and you decide. We do not start work and present a number afterwards, and we do not charge by the hour and let the clock decide what you pay.
Where the honest answer is that the repair is not ours to make — a communal riser, a failed booster, something inside another flat's demise — we will tell you that, help you identify it clearly, and put it in writing so you have something to send your managing agent. That is often the most useful thing we can do, even though it is not a repair.
The flat below
Almost every serious plumbing emergency in a Central London flat eventually becomes a conversation about someone else's ceiling. Escape of water travelling between flats usually engages the building's insurance rather than your contents cover, and the buildings policy is typically arranged by the freeholder or managing agent. Exactly how liability lands depends on your lease wording and the policy — check both rather than assume.
Practically: tell the flat below early, tell the managing agent early, photograph everything before it is cleaned up, and note the date and time you first noticed it and when it was stopped. A leak that was stopped promptly is a repair. A leak that was known about and left is an argument you will lose. Keep any parts that are removed — a failed flexible hose in a bag is evidence.
After the water stops
The repair is the beginning, not the end. Water that has been through a floor is still in the floor. Timber holds it, plaster holds it, and a room that looks dry in a week can still be wet in the joists. Drying properly before making good is the difference between a repair and a repeat.
The same applies to the cause. If a joint failed because the pipework is at the end of its life, replacing one joint buys you a few months. If a bath waste has been leaking quietly for a year, the trap is the least of the problem. We would rather tell you the honest scope than the cheap one.
And if this is the third call in two years, the answer is not another emergency. It is a planned look at the whole installation — which is what our maintenance service is for, and it is a great deal cheaper than replacing a neighbour's ceiling.
What to have ready before you ever need this
Know where your stopcock is and check it turns. Know whether your block has a porter and what the out-of-hours number is. Know your managing agent's emergency contact. Know whether your building has communal isolation and who holds the key. Have a couple of buckets and towels somewhere findable. That is the whole list, and it is worth ten minutes on a dry afternoon.
We cover W1, W2, NW8 and W9. If you need a plumber in Mayfair, Paddington or elsewhere in Central London, send a photo and tell us what is wet — and turn the water off while you wait.