Water is coming from the apartment above you.

Move everything out from under the water and keep people out of that area, then go up and knock. If nobody answers, call the building’s emergency maintenance line straight away and tell them which unit the water is coming from. Your own shut-off valve will not stop water that is arriving from someone else’s plumbing.

Why this is a different problem from a leak in your own home

Everywhere else on this site the first instruction is to close the main valve. Here you cannot. The water is on the other side of a ceiling, in a unit you do not control, fed by a riser that usually has no shut-off inside your walls.

What you actually control is three things: what is underneath, who finds out, and what gets recorded. That is the whole list, and doing all three well is worth more than anything else you could attempt.

In the first few minutes

1. Clear the floor underneath. Furniture, rugs, electronics, documents. Water finds the same path repeatedly, so what is under it now will keep getting wet.
2. Knock upstairs. Most of these are someone with an overflowing bath or a washing machine hose who has no idea. Thirty seconds of knocking often ends the event.
3. Call the building emergency line whether or not anyone answers upstairs. Building managers, superintendents, and managing agents have out of hours numbers precisely for this, and they can get into a unit when the resident is away.
4. Contain what is arriving. Buckets, and a towel underneath so the bucket does not splash. If the ceiling is holding a visible pocket of water, read what to do about a bulging ceiling first before you go near it.
5. Photograph and video everything, with a timestamp. This is the single most valuable thing you will do today, because the money question later is whose plumbing failed, and you will not be able to prove it after the ceiling has been repaired.

If nobody is answering and water is pouring in, ask the building to shut the riser. In most buildings that is a decision for the superintendent or the managing agent, not for you, and forcing entry into a neighbor’s unit is not your call to make.

What to write down

Take two minutes and note:

• The time you first saw water, and the time you reported it.
• Who you called, on which number, and what they said.
• Which unit it is coming from, if you know.
• Photographs of the ceiling, the walls, the floor, and every affected possession.

The reason to be this deliberate is that three parties may end up arguing about this: your insurer, the neighbor’s insurer, and the building’s insurer. The person with a time stamped record of who was told what, and when, does far better in that argument than the person with a memory of it.

Who actually pays

This is the part that surprises people, so it is worth being precise. There are usually three separate policies in play and they cover different things.

The building’s master policy typically covers the structure and common parts. In a condominium, how far it reaches into your unit depends on the governing documents. Some master policies cover the unit as originally built, some stop at the bare walls. Nobody can tell you which without reading yours.

Your own policy, whether a renters policy or a condominium unit owners policy, covers your contents, your improvements in many cases, and often your additional living costs if the unit becomes unlivable. This is the policy that usually does the practical work.

The upstairs neighbor’s policy covers their liability, but only if they were negligent. That is the thing people get wrong: a neighbor whose supply hose failed without warning is generally not negligent, and their liability cover does not automatically pay for your ruined floor. A neighbor who left a bath running is a different matter.

Which is why, if you are renting and you have no renters policy, the honest answer is often that nobody pays for your belongings. Who is responsible for what between a landlord, a tenant, and a building is worth reading before this ever happens, because renters insurance is cheap and this is exactly what it is for.

Report it to everyone, promptly

• Your own insurer, even if you think it will be someone else’s claim. Notice costs nothing and late notice is a common reason claims fail.
• The building manager or managing agent, in writing, following up the phone call.
• The landlord, if you rent, also in writing.

Ask the building for an incident report or a maintenance ticket number. It creates a dated record that you were not the source.

Do not fight over the repair yet

Two practical cautions.

Do not agree to a private arrangement with the neighbor before you know the extent of the damage. Water in a ceiling void spreads sideways along joists, and the wet area you can see is usually smaller than the wet area that exists.

And do not let anyone start opening up your ceiling before it has been documented, unless it is being done for safety. Once the drywall is off, the argument about where the water came from becomes much harder to win.

Then it becomes an ordinary drying problem

Once the water has stopped, what remains is wet material, and the clock is the same as anywhere else. The window is 24 to 48 hours from when material got wet.

The complication in a building is that the wet material is often shared: the ceiling void between you and the unit above is structure, not decoration, and it holds insulation and wiring. Drying a ceiling void properly needs equipment and access, which is another reason to have the building involved from the first hour rather than the second day.

The short version

You cannot shut this one off. Clear the floor, knock upstairs, call the building emergency line, and photograph everything with times. Report it to your own insurer as well as to the building. A neighbor is only liable if they were careless, so your own policy is usually the one that does the work.