Confusing leak problem

[AndyL]

HI all.

I'll be the first to admit I'm a bit of a novice when it comes to plumbing etc, but this is really baffling me.

A few days ago I noticed a slow, but constant drip coming from the circled area on the pics below.

The top of the sink, the tap, the pipes and the drain are dry.

Thge underside of the sink is dry.

The water is coming from the very narrow gap between the ceramic back of the sink and the tile, which as you can see is large and the grout is well away from the drip.

The builders when constructing the building didn't actually bolt the sink to the wall either, it's bolted to the floor and sealed along the top, but not underneath. So the tile is intact, at least from what I can see.

I've filled the sink to the overflow, and drained it, and the drip remains constant, it doesn't speed up at all.

I've turned the water off, and the same, it stays constant - this leads me to believe the issue isn't a leak in my system.

I live in a flat and do have a neighbour above and one below. I have had issues with a leak from the flat above once before but it was obvious as the water was coming through my light fixture and rapidly dripping onto the bathroom floor.

I would have thought thought that if this was a leak from above, or even within the wall, that I'd see more than just a slow drip of water under the sink where it'd have to have penetrated the tile. There's no discolouration or dampness on either side of the stud wall except for where this drip is. The water is clean, so doesn't seem like it's eroded through anything. It just seems to be coming from the bathroom side of the wall.

Someone suggested condensation, which certainly makes the most sense but the constant flow of water over the last few days, whether the bathroom has been used or not.

We're not talking alot of water, I've got a takeaway container under the drip at the moment and in 6 hours it;s not even covered the bottom, but I am concerned there's something more sinister causing it.

Any insights?

[dkerr]

Hi

you have checked most things.

some water can run along the fixture edge from the pipes or around the top. you said though that it is dry there. The top cocking seems ok in the picture on the edge the fixture there can always a bit of water that remains inside even after the tap is turned off. Any high humid air hitting a cold surface can condense.

Is there any moisture on any of the pipes?

Does the wall ceramic end as they meet the fixture or run behind the fixture?

I don't think it is that uncommon to have a pedestal sink only be mounted only to the floor, mine was like that until I changed it a cabinet as I preferred a cabinet / sink as opposed to pedestal one the builder put in.

Also check for cracks in the sink although had to see behind.

[AndyL]

Thanks for the reply dkerr

No, there is no moisture on the pipes at all.

The wall tiles run all the way to the floor and along the whole wall with no break. They come up I'd say about 1 foot above the sink where it's then dry wall where the mirror is mounted.

I've got someone coming in a day or two to help me get the sink off so we can take a look behind.

[ChrisB]

I would remove the sink from the wall and have a look. I could be something from above running down the inside of the wall and coming out a hole in the tile.

[AndyL]

Thanks Chris.

I've got someone coming to help me to that tomorrow afternoon. Will see what it finds but I'm fairly confident that there's no hole in the tile

[AndyL]

So I got the sink off. The tile and back of the sink were wet but no sign of any water coming through the tile.

Dried it all off and resealed the sink and no sign of any dripping at all now.

Must have been condensation just odd that it dropped for 5 days non stop