Plumbing 5 August 2026

Water Leaking Through the Ceiling? What to Do in the First Ten Minutes

If water is coming through a ceiling, do three things before anything else: turn the water off at the internal stopcock, switch off the lighting circuit for that room at the consumer unit, and get a container and towels underneath. Everything else — working out where it is coming from, who to ring, what it will cost to put right — can wait ten minutes. Stopping the flow and keeping it away from the electrics cannot.

This is one of the calls we take most often on the emergency line, and the damage bill almost always comes down to how the first few minutes went rather than how bad the original leak was.

The first ten minutes, in order

1. Turn the water off at the stopcock. In most houses it is under the kitchen sink; in older Kent properties it can be in a downstairs loo, a utility cupboard, under the stairs, or in the floor near the front door. Turn it clockwise until it stops. If yours is seized — and plenty are, because nobody touches them for twenty years — there is a second stopcock outside, usually under a small metal or plastic cover at the boundary of the property, and a long key or even a broom handle will reach it.

2. Kill the electrics to that area. Water tracks along joists and cables and comes out at the nearest hole in the plasterboard, which is very often a downlight or a ceiling rose. Do not stand under a light fitting that is dripping and do not switch it on to “see if it still works”. Turn off the lighting circuit at the consumer unit, and if water has already run through a light fitting or a socket, turn off the main switch and get an electrician to look before it goes back on.

3. Open the taps downstairs. Once the mains is off, running the cold taps and flushing the loo drains down what is still sitting in the pipework and in any loft tank, so less of it ends up on your floor.

4. Contain and protect. Bucket underneath, towels around it, lift what you can out of the room. If the ceiling is bulging, that bulge is holding several litres of water and it will eventually let go all at once — see below.

5. Then ring someone. By this point you have stopped it getting worse, which is the only part that is time-critical. We are on 01732 792 454.

Should you pierce a bulging ceiling?

A sagging, heavy-looking patch of plasterboard or lath and plaster is holding a pocket of water. Left alone it will come down under its own weight, taking a wider area of ceiling with it and soaking whatever is underneath.

If you are confident the electrics to that room are off, put a large container directly beneath the lowest point of the bulge and make one small hole in the centre with a screwdriver so it drains in a controlled way. It feels wrong — you are deliberately making a hole in your ceiling — but a single screwdriver hole is a filler repair, and a collapsed ceiling is a plasterer.

If you are not sure about the electrics, or it is lath and plaster in an older property, leave it, keep everyone out of the room and wait for an engineer.

Water coming through the ceiling: what it usually turns out to be

When our engineers lift boards on this kind of call, burst pipes are far from the most common cause. What we actually find, in rough order of frequency:

• Shower tray and enclosure seals. Water gets past a tired silicone joint or a cracked grout line, runs down the outside of the tray and onto the ceiling below. The giveaway is that it only leaks after someone has showered, and stops the rest of the day. We covered the repair in fixing a leaking shower.
• Waste and trap joints. A basin, bath or shower waste that has been knocked, or a compression joint that has worked loose. Again, use-dependent — it drips while the bath empties, not constantly.
• Loo pan connectors and overflowing cisterns. A perished pan connector seeps at every flush, and a failed float valve sends water down an internal overflow that often discharges somewhere you will not notice until the ceiling does.
• Sealed-system pressure relief and boiler leaks. Worth ruling out if the leak is under a boiler or airing cupboard — what to do if your boiler is leaking water walks through that separately.
• Genuine pipe failures. Corroded copper, a nail through a pipe from a floorboard or a carpet gripper, or a push-fit joint that was never pushed fully home. These are the ones that run continuously and get bad quickly.

Is it a plumbing leak or a roof leak?

The quickest test costs nothing: does it track the weather, or does it track the household?

Rain-dependent — it appears during or shortly after heavy rain, or after wind-driven rain from one direction, and dries out in settled weather. That is the roof, the flashing, a gutter overflowing back against the wall, or a blocked valley. A plumber is not the trade you need.

Use-dependent — it appears after a shower, a bath, a load of washing, or when the heating fires up, and there has been no rain for days. That is plumbing.

Constant — it never stops, wet or dry. That is a mains-pressure leak, and it is the one to treat as urgent.

Top-floor ceilings can honestly be either, which is where a look in the loft settles it: a wet felt or a stained rafter above the patch points at the roof; dry timbers with a wet ceiling below point at a pipe or tank.

Where the stain is tells you a lot

Water does not fall straight down. It runs along the top of the plasterboard until it meets a joist, then along the joist until it finds an exit — a downlight cut-out, a loft hatch edge, a pipe hole. So the wet patch is often a metre or more from the actual fault, and usually lower along the run rather than directly beneath it.

Which is why we lift a board rather than guess. On a job like this we work back from the wet patch towards the nearest wet joist end, then isolate the suspected fitting and run it to confirm, before anything gets cut.

Is it an emergency, or can it wait?

Treat it as an emergency and ring us straight away if: the water is continuous with the mains off at the stopcock, it is running through or near light fittings or sockets, the ceiling is sagging, or it is coming into a room you cannot isolate.

It can reasonably wait for a booked visit if you have isolated the fitting responsible — stopped using that shower, turned off the service valve to that basin — the ceiling is only damp-marked, and nothing electrical is involved. Damp plaster that has stopped getting wetter is a repair, not a crisis.

If you are not sure which of those you are in, ring and describe it. We would far rather talk it through on the phone than have someone spend a weekend with a bucket under a live problem.

What we do when we arrive

We isolate first, trace second, repair third. That usually means confirming the mains is off, checking the obvious suspects in the room above, then lifting the minimum amount of flooring needed to see the actual joint. Anything involving gas appliances is handled by a Gas Safe registered engineer — we are registered under 951167 — and if the leak has run through electrics, we will tell you plainly that an electrician needs to sign it off before it goes back on.

Our plumbing work is charged at £95+VAT for the first hour, which is always billable, then £47.50+VAT for each hour after. Materials are agreed with you before we fit or order anything, so there are no surprises on the invoice.

If water is coming through your ceiling right now, turn the stopcock off, keep clear of the light fittings and ring us on 01732 792 454. If it has stopped and you want it looked at properly before it comes back, get in touch and we will get you booked in.