01 Sept 2026
A brown ring on the ceiling that was not there last month, or water dripping onto your bathroom floor with nothing above you but your neighbour's flat. Inter-floor seepage is a common problem in stacked housing here, and a frustrating one, because the water is almost never coming from the spot where it lands.
Here is what to do, in order.
Contain it before anything else
Put a bucket or a basin under the drip and old towels around it. Move furniture, rugs and anything electrical clear of the wet area.
If water is running anywhere near a light fitting, a ceiling fan point, a socket or your distribution board, switch off that circuit at the consumer box. Do not stand in water to reach a switch, and do not push a hand up into a wet ceiling void to feel around. If you cannot get to the box safely, leave it and keep everyone out of the room.
Photograph it, with the date
This is the step people skip and later regret. Take clear photos of the ceiling, the stain, the drip and anything damaged, and make sure the date is on them. Keep photographing as it changes, because a stain that grows over three weeks tells a very different story from one that appeared once and dried.
Write down when it started, whether it is constant or comes and goes, and whether it worsens at particular times of day. If it gets worse in the evening when the flat above is showering, that is a genuinely useful observation. Note it while you remember it.
Tell the unit above, early and politely
Knock on the door before you do anything else formal. Most of these cases are settled between neighbours, and the tone of that first conversation tends to decide how the rest of it goes.
They may not know. A leak inside a slab or behind a wall shows up in your ceiling long before it shows up in their flat, so there is a fair chance they are hearing about it from you for the first time.
Notify your town council or MCST
Whether you are in an HDB block or a condominium, tell the managing body in writing as well as verbally, and attach your photos. It puts the problem on record with a date, and they handle inter-floor seepage regularly, so they can tell you what the process is in your block.
Why nobody can tell you the cause from a photo
Water travels. It runs along the top of a slab, follows a pipe, and comes out at the lowest or weakest point it can find, which may be some distance from where it got in. Guessing from the stain is unreliable.
The realistic causes are:
- Failed waterproofing in the bathroom or kitchen floor above, letting water through the slab
- A leaking pipe in the ceiling void, which may serve the unit above or may serve yours
- A leaking floor trap or waste pipe at the joint where it passes through the slab
- Nothing plumbing-related at all, such as condensation off air-conditioning pipework or trunking
That last one catches people out. Before you go further, check whether the damp patch sits near an aircon unit or its pipe run, because a sweating chilled line makes a stain that looks exactly like a leak.
Responsibility depends on where the water is actually coming from, and that is established by inspection rather than by argument. Nobody, us included, can tell you from a photograph who should be putting it right. What an inspection does is answer the question that decides everything else: what is leaking, and where.
What an inspection actually looks at
On the plumbing side it is a process of elimination. The pipework serving both flats gets checked and tested, the fittings and floor traps are looked at, and the pattern of the damp is read against how the flats are actually used. A leak that carries on with the supply shut off is not a supply pipe. A stain that only worsens after someone showers points somewhere different from one that seeps steadily day and night.
If the pipes test sound, that is a useful result too. It moves the question over to the waterproofing side instead of leaving you opening a ceiling for nothing.
We can carry out the plumbing half of this. Our leak repair work covers tracing and fixing the source, and there are short answers on seepage and stopcocks on our FAQ page. An on-site survey starts from $30 if you want the plumbing ruled in or out before the discussion upstairs goes any further.
When to call a plumber
Call when the drip is active rather than historic, when the stain is spreading, or when the conversation upstairs has stalled and you need an independent look at the pipework. Call straight away if water is near electrics, or if a ceiling board is sagging or bulging, because that is water pooling above it. A stain that has been dry and unchanged for a year can wait for a sensible appointment.