Water coming through a light fitting? What to do now.

Water dripping through a ceiling light is one of the most common calls we get in heavy rain, and after a burst pipe or an overflowing bath upstairs. The light fitting is where the water shows, because it is a hole in the ceiling. The risk is that the water is now in contact with the lighting circuit.

What to do right now

1. Leave the light alone. Don’t switch it on or off, and don’t touch the fitting or the switch.
2. Switch off at the fuse board, if it is safe to. If the fuse board is dry and you can reach it without standing in water, switch off the main switch. If the fuse board is wet, or water is running near it, don’t touch it: keep away and call us.
3. Slow the water down. If it’s a pipe, turn off the water at the stopcock. If it’s a bath or tank upstairs, turn off the tap or supply. Put a bucket under the drips where you can do it without standing under the light or in pooled water.
4. Don’t switch the power back on, even if the drips stop and the light looks dry. Water sits in the ceiling, in junction boxes and inside fittings for days.
5. Call an electrician to make it safe, and a plumber or roofer to fix the leak itself. If you rent, tell your landlord or agent straight away.
6. Take photos of the ceiling, the water and any damage. Your insurer will want them.

A fuse board that keeps tripping after a leak is usually the RCD doing its job: it has detected current leaking to earth through the water. Don’t keep resetting it; see RCD keeps tripping.

Why the water comes through the light

Water runs along joists, pipes and cables in the ceiling void until it finds a way out, and the light fitting or a smoke alarm is often the first gap it reaches. So the drip may be some distance from the actual leak.

Water in a smoke alarm

Mains smoke alarms sit on the ceiling and are wired in, so water often reaches them too. Moisture in the sensor can set off false alarms, or stop the alarm working when you need it. Mains alarms also have a backup battery, so they can keep sounding or chirping after you switch the power off. That doesn’t mean the power is still on.

We don’t trust a smoke alarm that has had water through it: it is a life-safety device, so we replace it, and check the interlink to the other alarms. Until then, keep at least one working alarm on each floor. See smoke alarm beeping and Aico mains alarms.

What we do when we come out

1. Make safe. Isolate the affected circuits so the rest of the house can stay on wherever it is safe: often you keep your sockets, fridge and heating while the lights are off.
2. Find where the water has been. Take down the affected light fittings and alarms, and check the junction boxes and cables in the ceiling where we can reach them.
3. Test before anything goes back on. We test the circuit’s insulation once it has dried. A light that “works” can still be leaking current through damp.
4. Replace what’s damaged. Light fittings, downlights and smoke alarms that have had water through them, and any corroded connections.
5. Write it up. You get a short report of what we found, what we isolated and the test results, ready for your insurer.

If the ceiling is still saturated, we leave the affected circuit isolated and come back once it has dried, rather than switching it back on too soon.

Real call-outs: water on the electrics

Since 2024 we have been called out more than 30 times to homes and blocks of flats where water has reached the electrics, mostly for housing associations and the contractors who look after their homes. These photos are from our engineers’ job reports. No names or addresses.

Waltham Abbey, September 2025: water inside a ceiling light

A leak from above had filled the diffuser of a ceiling light in a flat with water (the photo at the top of this page). Our engineer took the light down and made the circuit safe within half an hour of arriving.

Harrow, September 2025: a leak into a lift motor room

Water came through the ceiling of the lift motor room in a sheltered housing block. We isolated the lift motor room light and two other lights at the fuse boards, made them safe and took them down. Three days later, once it had dried out, we came back and fitted three new LED batten lights.

Watford, November 2025: sockets tripping in a kitchen

The kitchen sockets kept tripping whenever the fridge was plugged in. The boiler was leaking down behind the fridge and had soaked the extension lead it was plugged into. We dried the appliances out, replaced a socket that had burnt, tested the circuit and reported that a plumber was needed for the boiler.

Hackney, August 2025: lights back on after a leak

Two lights in a sheltered housing scheme had been taken down after a leak. Once the ceiling was dry we took both down again to check the connections: one was fine and went back up, the other had water damage and was replaced with a new LED fitting. Then the circuit went back on.

Stevenage, September 2024: water running down beside the sockets

Water was coming in and running down the wall next to a row of sockets in a flat. We were asked to attend within the hour, made the electrics safe, and went back to reinstate them once everything had dried.

Insurance

Many home insurance policies cover sudden water damage, such as a burst pipe (“escape of water”) or storm damage. Cover varies: wear and tear, and gradual leaks, are often excluded. Check your policy, report it to your insurer early, and keep our report and your photos. Landlords: see electricians for landlords.

Questions we’re asked

Written by SEGplc. Last updated 21 October 2026.