Mystery leak in my loo

[RustyNails]

I'm hoping some expert sleuth out there can help solve the mystery of my leaking loo.

There's been water leaking behind the toilet, and several visits from plumbers failed to solve it. It doesn't leak when you flush, but once every few days you'll come in and see water behind the stool. Sometimes it's a good bit, like a cup's worth, and other times just a few drops that I only noticed because I began laying bits of tissue down in spots behind the toilet and along the wall in order to easily see if it was wet. The first time I noticed it, there was a lot of water, all the way from the stool back to the wall (a few inches) and running all the way behind the toilet from the vanity to the wall on the other side of the toilet. So it was probably about 4 feet long, a few inches wide, and the water was a couple of inches deep. BUT I'm not the one who usually uses that bathroom and the person who does is rather unobservant -- meaning by the time I discovered the pool of water, it could've been building up for a couple months. I cleaned it up, and a few days later there was a pretty good bit again, but not nearly as much as the first time. There is no sign of leaking down into the basement, and a guy came out with a water meter thingy and determined that it was only a little wet under the flooring, not enough to worry about.

So, plumbers came a few times and couldn't determine what was wrong. They finally said the most likely culprit was a bad wax seal under the toilet, so I told them to go ahead and change that. When he got the toilet up, there wasn't really a definite problem with the seal, but he saw a little something that he said could've maybe possibly been a problem (I think he said a notch in the collar or something, not sure). So he left, and water showed up again behind the toilet. Another guy came out and replaced the "tank to bowl kit" which I guess is a rubber gasket thingy at the bottom of the tank, as he thought maybe water was dripping down from there. Yet the problem persisted.

A townhouse maintenance guy came out and looked at the window which is right above the toilet (it doesn't open, and has always been bone dry around the edges inside). He looked outside to see if it needed caulking to make sure water wasn't dripping into the wall there and then out under the baseboard), and it didn't need caulking. I asked if some vent or other thing on the roof could possibly be leaking down into the walls and then out under the baseboard behind the toilet, and he said he couldn't see how that could be happening.

Now for a few weeks, other than one time when a paper towel left behind the toilet turned up completely soaked, I only get a small bit of water showing up (enough to lightly wet part of the tissues I place behind the stool), but it keeps happening every two or three days. We have put green food coloring in the back of the tank, and the tissue I leave around the toilet is never colored green. We have filled the sinks with water and food coloring and let it all rush out at once, and no leak appears, so I really don't think it's from the sinks.

What I have been able to discern by putting bits of tissue here and there on the floor is that I think the water is originating from the back base of the toilet. I don't think it's coming from the area of the shut-off valve beside the toilet, nor from the wall behind the toilet, nor from the bathroom sink/vanity area. But it's not coming immediately out when we flush, it just seems to be randomly burping up water every now and then.

I've been told that if I can't figure out where it seems to be coming from, the next step is to rip out the vanity and rip open the wall behind the toilet. They may also take out the toilet and do some other thing under there (can't recall what they said). I really hate to get into god knows how much money to root around and try to find the problem, it would be much better if I can help direct them to the likely source.

Anyone have a clue what the problem could be?

 

[Reach4]

I was going to suggest that you get the user to sit when using the toilet.

But with your carefully placed piece of tissue, I would suspect the sewer line gets partially clogged at times. Has anybody been using a plunger on that toilet? To do further investigation, maybe use masking tape to apply tissue to higher spots. Under the tank. The upper part of the supply line, on the wall...

 

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[Plumber69]

I'm hoping some expert sleuth out there can help solve the mystery of my leaking loo.

There's been water leaking behind the toilet, and several visits from plumbers failed to solve it. It doesn't leak when you flush, but once every few days you'll come in and see water behind the stool. Sometimes it's a good bit, like a cup's worth, and other times just a few drops that I only noticed because I began laying bits of tissue down in spots behind the toilet and along the wall in order to easily see if it was wet. The first time I noticed it, there was a lot of water, all the way from the stool back to the wall (a few inches) and running all the way behind the toilet from the vanity to the wall on the other side of the toilet. So it was probably about 4 feet long, a few inches wide, and the water was a couple of inches deep. BUT I'm not the one who usually uses that bathroom and the person who does is rather unobservant -- meaning by the time I discovered the pool of water, it could've been building up for a couple months. I cleaned it up, and a few days later there was a pretty good bit again, but not nearly as much as the first time. There is no sign of leaking down into the basement, and a guy came out with a water meter thingy and determined that it was only a little wet under the flooring, not enough to worry about.

So, plumbers came a few times and couldn't determine what was wrong. They finally said the most likely culprit was a bad wax seal under the toilet, so I told them to go ahead and change that. When he got the toilet up, there wasn't really a definite problem with the seal, but he saw a little something that he said could've maybe possibly been a problem (I think he said a notch in the collar or something, not sure). So he left, and water showed up again behind the toilet. Another guy came out and replaced the "tank to bowl kit" which I guess is a rubber gasket thingy at the bottom of the tank, as he thought maybe water was dripping down from there. Yet the problem persisted.

A townhouse maintenance guy came out and looked at the window which is right above the toilet (it doesn't open, and has always been bone dry around the edges inside). He looked outside to see if it needed caulking to make sure water wasn't dripping into the wall there and then out under the baseboard), and it didn't need caulking. I asked if some vent or other thing on the roof could possibly be leaking down into the walls and then out under the baseboard behind the toilet, and he said he couldn't see how that could be happening.

Now for a few weeks, other than one time when a paper towel left behind the toilet turned up completely soaked, I only get a small bit of water showing up (enough to lightly wet part of the tissues I place behind the stool), but it keeps happening every two or three days. We have put green food coloring in the back of the tank, and the tissue I leave around the toilet is never colored green. We have filled the sinks with water and food coloring and let it all rush out at once, and no leak appears, so I really don't think it's from the sinks.

What I have been able to discern by putting bits of tissue here and there on the floor is that I think the water is originating from the back base of the toilet. I don't think it's coming from the area of the shut-off valve beside the toilet, nor from the wall behind the toilet, nor from the bathroom sink/vanity area. But it's not coming immediately out when we flush, it just seems to be randomly burping up water every now and then.

I've been told that if I can't figure out where it seems to be coming from, the next step is to rip out the vanity and rip open the wall behind the toilet. They may also take out the toilet and do some other thing under there (can't recall what they said). I really hate to get into god knows how much money to root around and try to find the problem, it would be much better if I can help direct them to the likely source.

Anyone have a clue what the problem could be?

Open tank and flush, Is anything spraying out. I 8nce had a problem like this, turns out the tank would fill past the handle opening and drip out quite a bit. it would only happen every maybe 10 flushes

 

[JohnnyS]

What kind of toilet is it? Is there any water on the toilet tank or bowl or is it only on the floor? Is the angle stop a multi-turn? If it is make sure the packing nut isn't leaking. Take the tank lid off, flush the toilet and make sure the overflow hose is spraying into the overflow and not anywhere else.

 

[RustyNails]

I was going to suggest that you get the user to sit when using the toilet.

But with your carefully placed piece of tissue, I would suspect the sewer line gets partially clogged at times. Has anybody been using a plunger on that toilet? To do further investigation, maybe use masking tape to apply tissue to higher spots. Under the tank. The upper part of the supply line, on the wall...

Nope, I don't think we've ever used a plunger in there, and certainly not in the past year. I have had tissue scotch-taped to what I would call the supply line, and it's stayed bone dry. This is the hose with a valve that comes up through the floor and attaches to the underside of the tank to provide water. We don't a line that runs into the wall.

 

[RustyNails]

Open tank and flush, Is anything spraying out. I 8nce had a problem like this, turns out the tank would fill past the handle opening and drip out quite a bit. it would only happen every maybe 10 flushes

I just went back and did that, and nothing sprayed out and it didn't overfill the tank. Whatever it is, it's tricky!

 

[RustyNails]

What kind of toilet is it? Is there any water on the toilet tank or bowl or is it only on the floor? Is the angle stop a multi-turn? If it is make sure the packing nut isn't leaking. Take the tank lid off, flush the toilet and make sure the overflow hose is spraying into the overflow and not anywhere else.

It's an American Standard Comfort Height toilet. The shut-off value isn't leaking, I've got toilet paper taped to it to make sure it's not leaking. I took the lid off the tank, nothing sprayed about when flushed.

I also checked the tissue on the floor again. What I found was with the pieces jammed slightly under the back edge of the pedestal, just the edge that was under the toilet was wet a bit and the rest of the sheet wasn't. And by wet, I mean the paper was actually a bit stiff, like it had been slightly wet and dried quickly. On the other side, the tissue between the hose/valve and the pedestal, the paper seemed to be stiff all over, as though the whole thing had gotten slightly wet and dried. But that could've been from water coming from under the stool and not from the valve area, as the tissue on the valve was dry. Other tissue up against the wall was dry (I was told water could possibly be coming under that wall from somewhere, and I'm trying to determine if that's happeing). I was also told maybe the floor just gets wet when it rains and it is somehow coming in from outside, but we had torrential rains for several days last week and the floor stayed dry.

 

[Smooky]

If the water going into the toilet is cold and the air in the bathroom is warm and moist it could be condensation forming on the outside of the tank and dripping on the floor. If that is the case it might only happen when somebody is taking a hot shower. An exaust fan in the loo might help if that is the case. There are valves that allow warm water to mix with the cold water when the toilet tank is filled. Sometimes tanks have a foam liner to prevent condensation.

 

[RustyNails]

If the water going into the toilet is cold and the air in the bathroom is warm and moist it could be condensation forming on the outside of the tank and dripping on the floor. If that is the case it might only happen when somebody is taking a hot shower. An exaust fan in the loo might help if that is the case. There are valves that allow warm water to mix with the cold water when the toilet tank is filled. Sometimes tanks have a foam liner to prevent condensation.

It's definitely not condensation. There have been times when it was a flood of water back there, to times when it was less but still enough to make a paper towel be sopping wet as though run under a faucet. It's less now, but definitely not condensation.

 

[Jadnashua]

It could be leaking from the connecting bolts that hold the tank to the bowl. It might hold fine most of the time, but depending on whether the user leans on the tank, and how much, it might leak. Ideally, the tank is installed with four washers and nuts. If there's a metal washer inside the tank, it can cause leaks. So, it should be rubber washer and head of the bolt inside; a metal washer and nut on the bottom side of the tank that creates the seal when tightened, then a second washer and nut underneath in the bowl to hold the now watertight tank to the bowl.

 

[RustyNails]

It could be leaking from the connecting bolts that hold the tank to the bowl. It might hold fine most of the time, but depending on whether the user leans on the tank, and how much, it might leak. Ideally, the tank is installed with four washers and nuts. If there's a metal washer inside the tank, it can cause leaks. So, it should be rubber washer and head of the bolt inside; a metal washer and nut on the bottom side of the tank that creates the seal when tightened, then a second washer and nut underneath in the bowl to hold the now watertight tank to the bowl.

A plumber changed the "tank to bowl kit" to make sure it wasn't leaking out of the bottom of the tank; is that the same thing you're talking about?

 

[Jadnashua]

Probably not...the tank-to-bowl gasket is what seals the tank to the bowl. The bolts that hold the tank to the bowl are different, and they must prevent water from leaking out of the bowl AND hold the tank in place. The tank-to-bowl gasket is in the center...the tank-to-bowl attachment bolts are off to either side.

 

[RustyNails]

Probably not...the tank-to-bowl gasket is what seals the tank to the bowl. The bolts that hold the tank to the bowl are different, and they must prevent water from leaking out of the bowl AND hold the tank in place. The tank-to-bowl gasket is in the center...the tank-to-bowl attachment bolts are off to either side.View attachment 32454

 

[RustyNails]

I know the plumber did something regarding the bolts, too, so I don't think that's it. I'm wondering if it could be the vent stack? We have stopped using that toilet for about 5 days, and no leaks since. I wanted to go a week or two to make sure there are no leaks when not in use (the plumber suggested this, we're trying to narrow down if the leak is from the toilet, sink or shower). When it is in use, it doesn't leak after every flush, only every few days. And there is sometimes an odd smell in that bathroom that I can't place, and cleaning and spraying disinfectant hasn't killed it. But it's not there constantly, and it's not overpowering, just kinda bad. Today I mentioned to my husband what I read about how when a vent stack is clogged it can cause a smell of sewer gas, and he immediately said, "That's it!" He seems sure the smell is sewer gas. The question is, could that also cause only intermittent leaking of water? And how much is that gonna cost to fix? (If that's the problem, of course we fix it no matter the cost, but it would be good to have an idea).

However, we have not had slow draining of water or gurgling sounds, which are listed as signs of a blocked vent.

 

[Smooky]

It is not the vent. Is the overflow at the right height? Have you replaced the fill valve? How about a good picture of the plumbing inside the tank?

 

[Reach4]

When it is in use, it doesn't leak after every flush, only every few days. And there is sometimes an odd smell in that bathroom that I can't place, and cleaning and spraying disinfectant hasn't killed it. But it's not there constantly, and it's not overpowering, just kinda bad. Today I mentioned to my husband what I read about how when a vent stack is clogged it can cause a smell of sewer gas, and he immediately said, "That's it!" He seems sure the smell is sewer gas.

With sewer gas, the most probable cause is the seal on the closet flange -- wax or waxless. A cracked toilet is a possible cause, but less probable. You have had the wax replaced, but I don't know if you had a sewer gas symptom all along.

At this point, I would be thinking a new toilet with a new install. You have tried other stuff.

 

[Jadnashua]

If the toilet base was not caulked, it could just be a lot of gunk that found its way underneath the base. Removal and a good cleaning may resolve the problem.

 

[r.g.]

I was going to suggest that you get the user to sit when using the toilet.

But with your carefully placed piece of tissue, I would suspect the sewer line gets partially clogged at times. Has anybody been using a plunger on that toilet? To do further investigation, maybe use masking tape to apply tissue to higher spots. Under the tank. The upper part of the supply line, on the wall...

When one sits on a toilet it is not unusual for one to lean back. When this is done on modern toilets that only have a two bolt tank to bowl attachment it can cause the tank to leak. But only when you're leaning on it. As soon as you stand, it stops. Condensation. If the water is colder than the room temp the toilet will sweat. Always in use so the water in the tank never reaches room temp. Or.. Ball cock or flush valve leaking Start checking for leak at highest possible point. Use yer finger! Any moisture on it and you'll know. Wipe finger around and then look a it. It will show the smallest leak. But... It's the tank to bowl gasket,bolts or flush valve nut was not snugged up before installation. Bet

 

[RustyNails]

With sewer gas, the most probable cause is the seal on the closet flange -- wax or waxless. A cracked toilet is a possible cause, but less probable. You have had the wax replaced, but I don't know if you had a sewer gas symptom all along.

At this point, I would be thinking a new toilet with a new install. You have tried other stuff.

When the plumber changed the wax ring, wouldn't he have seen it if there was a crack? Is there someway to check for the crack to be sure that's the problem before I shell out for replacing the toilet?

 

[RustyNails]

When one sits on a toilet it is not unusual for one to lean back. When this is done on modern toilets that only have a two bolt tank to bowl attachment it can cause the tank to leak. But only when you're leaning on it. As soon as you stand, it stops. Condensation. If the water is colder than the room temp the toilet will sweat. Always in use so the water in the tank never reaches room temp. Or.. Ball cock or flush valve leaking Start checking for leak at highest possible point. Use yer finger! Any moisture on it and you'll know. Wipe finger around and then look a it. It will show the smallest leak. But... It's the tank to bowl gasket,bolts or flush valve nut was not snugged up before installation. Bet

I will look into this, thanks.