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Plumbing in the Home/Diagnosing a leaking living room ceiling



I'm at my wits end trying to figure this one out. For the past two months or so, I've had a slow leaking ceiling. The leak (only a few drops every few hours) is coming from a golf ball sized hole that's located under the drain of an upstairs shower/tub. I've already had two plumbers over to take a crack at fixing it, but the leak continues. The first plumber replaced the flange of the toilet in the same bathroom as the tub and re-caulked the tub surroundings (since the tile where the tub meets the wall had deteriorated.) The second plumber was able to access the other side of the wall that the shower head, downspout, etc are located on. He determined that there was a leak at the pipe attached to the downspout and fixed it. I thought that would do it, but ceiling leak continues to drip at the same rate. I assumed that the drain pipe was leaking because the hole seems to be located directly below the tub drain. However, I shut off the water to the entire house the other day for a few hours and the leaked stopped completely. So the leak has to be coming from pipes with running water and take the drain possibility out of play, right?


ANSWER: Hi Peggy,
A leak above a ceiling is something that needs to be handled. It's more than just an annoyance, it can create a serious mold problem and potentially rot out structural members.  

The only real way to find the leak is to stop guessing, bite the bullet and open the ceiling under the tub/shower.  Leaking water seeks its own level and the leak may be coming from someplace other than where it is actually showing up. You must open the ceiling to find where its coming from.
Good Luck,

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QUESTION: Hi again, Dana,

So I cut open the ceiling. Now I'm 99% sure the leak is coming from a joint in the water supply line to the toilet. The joint is underneath the floor to the bathroom and extremely difficult to access from above or below (even with my small hands). I can barely reach it with my hand which is how figured out where the leak was coming from.

My question is, do you think it would be able to stop the leak with epoxy putty or some other sealant? I don't have plumbing skills and I"m reluctant to call another plumber (already paid two even though they didn't fix the actual leak). Plus, I think it will be an extremely expensive job since the pipe is so hard to access (behind a big PVC pipe).


Hello again Peggy,
One thing you didn't mention was what type of piping you have. The repair method really depends on that.
If its copper, it might be able to be repaired in place. If its galvanized steel, it going to be a bigger job.
It MIGHT be possible to seal the leak in the short term with epoxy putty but I wouldn't put a lot of faith in that, especially if it's an active leak. I've tried with not much success myself.

Given the location of the leak, you might need to remove the toilet and open the wall or come from the other side if possible.  This is going to take a plumber unfortunately.

Good Luck,

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Dana Bostick


Pretty much any residential plumbing questions. For "item specific" details such as a specific model of fixture, I will need to research and there may not be any useful information available. Note: I live and work in Southern California. We do not, as a rule, use hot water or steam heating systems, oil fired boilers or private water wells so my knowledge in those areas is pretty limited. There are others here on AllExerts that can probably answer those questions better.


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