A Water Stain on the Ceiling: Bathroom Above, Roof, or Something Else?

A brown ring on the ceiling is the most misleading symptom in plumbing. Water does not fall straight down. It runs along a joist, follows a wire, collects at a low point and comes through the lining somewhere else entirely, so the stain almost never sits under the thing that caused it.

The good news is that you can narrow it down a long way before anybody opens anything, and the questions that do it are simple.

When does it get worse?

This one question sorts most ceiling stains into the right pile.

After rain, and only after rain. That points at the roof, a flashing, a spouting overflow or a window head. Not a plumber’s job, although we will tell you honestly if that is what we think it is.
After someone showers or uses the bathroom above. That is a waste or a waterproofing failure upstairs. It stops between uses because nothing is draining.
All the time, wet or dry, rain or no rain. That is a supply pipe under pressure, and it is the urgent one, because it is running twenty four hours a day.
Worse in cold weather, no upstairs bathroom, spread evenly rather than a defined ring. That is more likely condensation than a leak.

Keep a note over a few days rather than guessing. It is the single most useful thing you can hand us.

The stain is under the bathroom. Is it definitely the bathroom?

Usually, but not always the fixture you would expect.

At a property in Murrays Bay water was coming through a bedroom ceiling and mould was forming in the wardrobe below. The source was the toilet directly above, where both the fill valve and the flexible supply hose were leaking. In Flat Bush the reported leak was from the upstairs bath, and once we cut the ceiling open below, it turned out to be the bath waste connection, which we removed and reinstalled correctly. In Hobsonville water had escaped across a tiled bathroom floor toward the door and gone through to the ceiling below, and no pipe was leaking at all: the floor had been washed down with water. New Zealand bathrooms are not wet rooms, so the floor outside the shower is not built to have water poured on it.

Same symptom in all three, three different repairs. This is why an honest plumber will tell you what they suspect and the order they will check in, rather than promising the cause before anything comes apart.

My water meter is not moving. Does that rule out a leak?

No, and this is worth knowing because it sends people down the wrong path.

We attended a townhouse in Takapuna where the tenant reported water dripping from the ceiling above the downstairs bathroom, with wallpaper lifting in the bathroom and hallway and the hallway carpet damp. On the first visit we checked the fixtures above, moisture tested the walls, and monitored the water meter. The meter was not moving at all. That did not mean there was no leak. It meant the leak was slow enough that it did not register, which is exactly what a concealed weep looks like.

A moving meter proves a leak. A still meter proves nothing on its own, particularly when there is already visible water damage.

Ceiling and wall linings opened up progressively to trace a concealed leak

Do you have to cut the ceiling open?

Often, eventually, and we do it as late and as little as we can.

On that Takapuna job we recommended opening the linings after the first visit and got approval before doing it. On the second visit we opened the ceiling and wall progressively, tracing as we went rather than taking out a whole sheet, and found a slow leak at a corroded tee fitting on the water supply pipework concealed in the wall.

That is the honest shape of these jobs. There is an investigation stage and a repair stage, they sometimes happen on different days, and the investigation is charged even though it has not fixed anything yet.

It also means we cannot give you a repair price at the start. A leak inside a wall or under the ground is hard to locate and, until it is open, there is no way to know how much pipe is affected or how much has to come out. So we quote the investigation, and then quote the repair once we can see it. That is not us being evasive, it is the only order the information arrives in.

Who puts the ceiling back?

A builder, and that is a separate quote from ours.

We cut the lining to reach the pipe, and our work finishes when the plumbing is repaired and tested. Patching or replacing the gib, stopping, sanding and painting is building work, not plumbing, so it is not in our price and we do not include it. Ask us and we will tell you roughly what is involved, but the number has to come from a builder.

Worth knowing before you start, because people often assume the plumbing quote covers the hole afterwards. It never does.

A corroded tee fitting removed from inside a wall, the cause of a slow ceiling leak

Can you stop it today even if you cannot fix it today?

Usually yes, and it is often the right call.

In Northcote we found a burst Buteline supply line feeding a toilet, concealed inside a wall, with the water accumulating in the wall and ceiling space and dripping down from there. A permanent repair meant removing the toilet, lifting tiles and opening the wall, which is not a same day job. So we isolated that line from within the ceiling space instead. The leak stopped immediately. The toilet was out of service until the proper repair, and the house stopped taking on water in the meantime.

Being without one fixture for a week is almost always better than a week of water in a ceiling.

Should I claim this on insurance?

Worth thinking about properly, because the answer genuinely differs depending on how wet things got.

A small repair is usually not worth claiming. If it is one fitting, a bit of lining and a repaint, the cost may not be far off your excess, and a claim on the record can affect what you pay at renewal. A lot of people are better off simply paying for a job like that.

Serious wetting is a different matter, and you should claim. Once carpet has to be lifted and dried, framing and insulation need drying out, ceilings and walls have to be rebuilt and rooms repainted, the total goes well past what most people expect, and that is exactly what the cover is for. Do not try to absorb that one.

Either way, get the plumber’s report. That report is what the claim runs on: what failed, where it was, when it was found, and whether it was sudden. On a concealed ceiling leak, where an insurer’s first question is whether this was gradual damage, that document is worth more than anything else you can put in front of them.

How urgent is it?

Treat these as urgent, more than the size of the stain suggests.

Water sitting in a ceiling cavity soaks the framing and the insulation, both of which hold it against timber for a long time afterwards. It finds light fittings, which is an electrical risk rather than a plumbing one. And a saturated ceiling can come down in one piece with no warning.

If the ceiling is sagging, bulging, or the paint is holding a bubble of water, keep everyone out of that room, turn the power off to it at the board, and ring us. Do not poke it while standing underneath.

Seeing a stain and not sure which of these it is? Send us a photo and tell us when it gets worse. That is usually enough for us to tell you what we think you are dealing with before anyone comes out.

Common questions

Should I paint over it once the leak is fixed?

Not straight away, and not with ordinary paint. The lining needs to dry out completely first, which takes longer than people expect, and the stain will bleed through normal paint even when dry. A stain blocking sealer goes on first, then the paint. Painting early also hides the evidence you need if the leak comes back, so leave it visible until you are confident it is dry.

The stain has stopped growing. Has it fixed itself?

Leaks do not repair themselves, but they do pause. A waste leak stops whenever the fixture is not being used, and a roof leak stops between rain. A stain that has gone quiet usually means the conditions changed, not that the fault went away. Mark the edge of the stain in pencil with the date on it, and you will know for certain next time whether it has moved.

Is the mould dangerous?

Mould in a wardrobe or on a ceiling is a sign that the material behind it has been damp for a while, so the real issue is the water, not the spores. Cleaning it off without stopping the source just means it returns. Once the leak is repaired and everything is properly dried, the mould can be dealt with and it should not come back.

What does insurance actually cover here?

The damage rather than the pipe. A sudden failure that wrecks ceilings, carpet and contents is normally treated as accidental damage, while finding and repairing the pipe itself sits with you. The trap with ceiling leaks is that they are slow and concealed by definition, so the question of whether this was gradual damage comes up almost every time, which is why the report matters.

Can you find it without opening anything?

Sometimes. Moisture meters, checking the fixtures above and monitoring the meter will often narrow it to a wall or a fixture, and occasionally the cause is obvious from the room above. But a concealed pipe inside a lined wall cannot be seen, and past a certain point the choice is between opening a small area deliberately or guessing. We would rather open one careful hole than replace a ceiling that was never the problem.