Water coming through a ceiling: what to do first

Water on a ceiling is two problems at once. The stain is what you can see. The dangerous part is what the water is reaching: cables, a light, and plaster that may not hold. This page is the first hour. It is not a method for opening floors, piercing plaster, or working on a boiler.

Electrics, then the stopcock

If water is near a light, a smoke alarm or a ceiling rose, treat the circuit as live and wet.

• Keep people out of the room, and out from under a bulge. A bulging ceiling can hold a lot of water and can come down in one piece.
• Do not use a wet light switch, and do not stand in a puddle to reach the consumer unit.
• Switch the electricity off at the consumer unit only if you can reach it from a dry place, with dry hands. If you cannot, leave it and call a qualified electrician.
• Once water has touched wiring, fittings or the consumer unit, have a qualified electrician check that circuit before it is used again. Electrical Safety First recommends an electrician registered with a government-approved scheme.

Some electrical work in homes has to be notified. In England, Approved Document P explains when notification is required. We do not give wiring instructions. Ask a qualified electrician whether the repair has to be notified. Wales, Scotland and Northern Ireland have their own rules. Turning the water off is not electrical work. Repairing soaked cables is.

Then stop more water arriving. Close the internal stopcock, clockwise, and open a cold tap downstairs to confirm the supply has stopped. Where stopcocks are, and what to do if one will not turn, is in find a leak and the stopcock. Do not force a seized stopcock. Use an outside stopcock only if you know it is yours to operate, or ask the water company.

If the water is hot, or it is from a heating pipe, turn the heating off at the programmer or the boiler's user controls. Do not open the boiler casing, and do not operate valves underneath the boiler. Gas work waits for a Gas Safe registered engineer. See when to call a Gas Safe engineer.

What the water is telling you

• Clean and cold, and it stops after the stopcock is closed: a mains pipe, a toilet fill, or a cistern still being fed.
• Clean and hot, or it continues after the stopcock is closed: stored hot water, a shower mixer, or a pipe that was already full.
• Rusty, black or oily, often with the heating on: a radiator or a heating pipe. Keep it off skin and furnishings, and call a plumber. A leak at the boiler is a Gas Safe job.
• From the loft, with an overflow running: a cistern that will not stop filling. See overflow pipes and loft cold water tanks.
• Only when it rains: the roof, a flashing, or a pipe that leaks when it is used. Say whether it happens in dry weather. A roofer and a plumber are different trades.
• Foul-smelling: not a clean-water leak. Keep clear, and read drain smells.

A leak that showed up after a thaw may be a burst. What not to use on a frozen pipe is in frozen pipes.

Finding the source

Work upwards, and only where it is dry and safe.

1. The room above. Look under the bath, behind the toilet, in the shower and under the basin. A wet panel is often the whole storey. See bath panels and traps.
2. What was used last. A shower, a washing machine, a toilet that keeps filling, or a radiator. Isolate that fitting if it has its own valve, then watch. Isolation valves shows which way is closed.
3. The loft, if the stain is on the top floor and you can get there without stepping through the ceiling. Look at the cistern, the overflow and the pipes. Do not walk on plasterboard.
4. A flat above. Knock, or call the managing agent. You cannot isolate their plumbing from your side.

Do not drill the bulge, and do not pull wet plaster down to see better. You can hit a cable or a pipe, or bring the ceiling down. Note the time, whether the heating was on, and whether the drip stops when the stopcock is closed.

Who to call

Call a qualified electrician when water has reached lights, switches or the consumer unit, even if the drip has stopped.

Call a plumber when the source is a pipe, a trap, a shower or a cistern you cannot isolate, and whenever the ceiling is sagging. If you rent, tell the landlord as well. Who usually arranges the repair is in tenant and landlord plumbing repairs. That page is not legal advice and it is not your tenancy.

Call the insurer when the building or belongings are damaged, and ask before you throw things away. What to photograph, and how a sudden leak differs from a long drip, is in leak insurance claims. If the water is from a neighbour, tell them, the managing agent and your own insurer. Their buildings policy and your contents policy are not the same thing.

Leave wet circuits off until an electrician has cleared them. When you open the stopcock again, do it slowly and watch the place that leaked.

Should I turn the stopcock off for a ceiling stain?

Yes, if water is still arriving or you cannot see the source. Closing the stopcock limits the damage while you look. An old, dry stain can wait for daylight. Wet electrics cannot.

Is a wet ceiling light safe to switch off at the wall?

Not from that switch, and not if you or the switch are wet. Use the consumer unit only from a dry place. Otherwise keep clear and call a qualified electrician.

Who pays when the flat above leaks?

That depends on the cause, the leases and the policies. Tell the neighbour, the managing agent and your insurer, and keep photos. The insurance guide says what to record. It does not decide whose policy pays.