What counts as a plumbing emergency in a London flat

Most plumbing problems feel urgent when they happen. Only some of them are. The test is simple: is water, or sewage, causing damage or danger right now, and can you stop it yourself? If the answer is yes and no, you need an emergency plumber. If you can stop it, you probably have a repair that can be booked.

Living in a flat changes the test. More than half of London households live in a flat, maisonette or apartment, according to the 2021 Census. In a flat, a leak that would be a nuisance in a house can be soaking through your neighbour’s ceiling within minutes.

The quick test

Ask yourself four questions.

1. Can I stop the water at a tap, an isolation valve or the stop tap?
2. Is the water near sockets, lights, a fuse box or appliances?
3. Could the water reach another flat, a shared hallway or a basement?
4. Do we still have water and at least one working toilet?

If you cannot stop it, if electrics are involved, if it is reaching someone else’s home, or if you have lost water or your only toilet, treat it as an emergency.

Call now, or make safe and book

Problem	Emergency?	What to do first
Pipe split and spraying	Yes	Stop tap off, electrics off near the water, open cold taps
Water through the ceiling	Yes	Electrics off if near lights, catch the water, go upstairs
Toilet overflowing, will not stop	Yes	Lift the float or close the cistern valve, stop flushing
Sewage coming up in a basement or shower	Yes	Stop using water, keep clear, report it
No water at all, neighbours have water	Usually	Check your stop tap is open, ask the managing agent about pumps
Stop tap will not turn and something is leaking	Yes	Look for isolation valves near the leak or the outside stop tap
Dripping tap	No	Book a repair
Slow draining sink	No, unless it is backing up	Stop using it and book
Toilet running constantly	Not usually	Close the cistern valve and book
Small leak you have stopped at a valve	No	Leave the valve shut and book

Why flats raise the stakes

In a Victorian house split into flats, the bathroom above is often built over a bedroom or living room below. Pipes run under the floorboards between the two homes. A small leak upstairs can stain the ceiling below before anyone upstairs notices a thing. That is why a leak that “is only a drip” can still count as an emergency if it is going somewhere you cannot see.

In mansion blocks, which are common across Westminster, bathrooms are stacked on top of each other and pipes run through shared risers. A leak in a riser can show on several floors at once. If you live in one of these buildings and water is coming in, call the porter or managing agent as well as a plumber. The Leasehold Advisory Service says the freeholder is usually responsible for communal pipes and tanks that serve more than one flat, while each leaseholder looks after pipes and appliances serving their own flat.

If the water is coming from upstairs, the emergency is partly someone else’s. Knock on their door. If nobody is in, the managing agent usually has a power under the lease to get access. Our guide to a leak from the flat above goes through who does what.

When it is not a plumbing emergency at all

Some situations need someone other than a plumber, and some need them first.

• You smell gas. Stop. Go outside and call the National Gas Emergency Service on 0800 111 999. Do not use light switches or flames. Gas work in the UK must be done by a Gas Safe registered engineer, so ask to see their ID card and check it on the Gas Safe Register.
• There is danger to life. A bulging ceiling that could come down, water pouring into the electrics with no way to switch off, or anyone trapped. Call 999. London Fire Brigade attends floods of all kinds, though it says that for a leaking tap it is probably best to call a plumber.
• Water is pouring out of the road or pavement. That is a Thames Water main or communication pipe. Report it to Thames Water online or on 0800 316 9800.
• The power has gone off across the street. Call 105.

The first five minutes

Whatever the problem, the same steps buy you time.

1. Turn off the water. The stop tap is usually under the kitchen sink, in an airing cupboard, under the stairs or near the front door. Thames Water notes that flats may also have a communal valve where the supply enters the building. Turn it clockwise.
2. Make the electrics safe. If water is near sockets or lights, switch off at the consumer unit, as long as you can reach it without touching anything wet.
3. Turn off the boiler or immersion heater, then open the cold taps to drain the pipes.
4. Contain the water with towels, buckets and bowls. Move what you can.
5. Take photos of the source and the damage. Insurers expect you to have taken reasonable steps to limit the damage, and photos show that you did.
6. Tell people. The flat below, the flat above, your landlord or managing agent, and your insurer.

What can wait until morning

If you have stopped the water, the electrics are safe and the home is usable, a night call may not be worth it. A daytime visit is usually easier to arrange and costs less. The exceptions are when there is no working toilet in the home, no water at all, or someone vulnerable lives with you and needs water or heating.

Leave isolated valves shut until the plumber arrives. Do not try to reconnect a split pipe with tape and turn the water back on. A temporary fix that fails at 3am causes more damage than a dry night with the water off.

A note on renting

If you rent, your landlord must keep the installations for water supply and sanitation in repair under section 11 of the Landlord and Tenant Act 1985. Use your landlord’s or letting agent’s emergency line first if there is one. If nobody answers and water is causing damage, make the home safe, keep receipts and tell your landlord in writing as soon as you can.