Mold is showing up on floor molding along adjoining wall with next unit. Units are mirror images and black staining is present on both sides of the fire wall. No other signs of water damage except along floor molding, side of vanity has absorbed water and bubbling of linoleum near vanity. Walls and ceilings appear fine. Seepage is worse when neighbors are home. Plumber has been here 3 times no resolution to date . Any ideas would be appreciated .

Did the plumber go into the adjoining unit? That sounds like where it's coming from. Maybe the wax ring has dried up or was seated incorrectly, who knows. Or basin overflow leaks, or even the trap.

Did the plumber go into the adjoining unit? That sounds like where it's coming from. Maybe the wax ring has dried up or was seated incorrectly, who knows. Or basin overflow leaks, or even the trap.

The plumber finally lifted their toilet and replaced the wax ring and installed a plastic cone. Cut holes in their walls and mine, no leaking pipes. Where is the trap and would lifting their toilet resolve that problem? I still have seepage but could that be residual from what has already occurred? Thanks much for responding . They have a tile floor and tile molding , my molding is wood.

Since you said slab I assume you're on the ground floor. Have you talked to your neighbors? Is the seepage worse when they take a shower or drain a fixture? What fixture would that be? Get the neighbors involved. While the water may come from the neighbors the leak appears to be in your apartment. Can you furnish more details?
Back to you, Tom

Since you said slab I assume you're on the ground floor. Have you talked to your neighbors? Is the seepage worse when they take a shower or drain a fixture? What fixture would that be? Get the neighbors involved. While the water may come from the neighbors the leak appears to be in your apartment. Can you furnish more details?
Back to you, Tom

We are both in a two story townhouse and the neighbors are not cooperative. We have tried all different scenarios on our side. Even when we have been gone for 8 hours seepage is still present when they are home it is worse. This has been going on now for about 6 weeks from when we first noticed our floor molding. Paper towels on the floor pushed under the molding absorb water.

Can you confirm that this is a first-floor leak. Do you have a condor Association? If so get them involved. Find out what fixture the neighbors are flushing or draining that causes your leak. This is important for the plumber to know.
Good luck, Tom

Can you confirm that this is a first-floor leak. Do you have a condor Association? If so get them involved. Find out what fixture the neighbors are flushing or draining that causes your leak. This is important for the plumber to know.
Good luck, Tom

The management company got the plumber we thought that would be best so it would be an unbiased party! We have no evidence anywhere else in our unit of water leaking and we have been looking . The plumber has been here 3 times, he does seem inexperienced and calls his boss often. I had to convince him to pull their toilet since 3 months ago they started a Reno of that bathr

Can you confirm that this is a first-floor leak. Do you have a condor Association? If so get them involved. Find out what fixture the neighbors are flushing or draining that causes your leak. This is important for the plumber to know.
Good luck, Tom

The management company got the plumber we thought that would be best so it would be an unbiased party! We have no evidence anywhere else in our unit of water leaking and we have been looking . The plumber has been here 3 times, he does seem inexperienced and calls his boss often. I had to convince him to pull their toilet since 3 months ago they started a Reno of that bathroom. Considering shutting off water main and moving out for a week to prove its not our side. Any other options you can supply?

By trap I meant under their sink.
What fixtures do they have directly behind your wall? Vanity and toilet?

By trap I meant under their sink.
What fixtures do they have directly behind your wall? Vanity and toilet?
Yes vanity and toilet. We have shut off our water main flushed and ran all toilets and faucets. Shut valve To washing machine. After 2 hours there is more wetness on paper towels. Taking pictures changing paper towels and monitoring if neighbors are home. Trying to rule in or out if it is our unit that has the leak although all people seem to agree its not from us.Any and all ideas are welcome and appreciated!

Is the cutout in the wall still out, so you can look in there when they are home? Does it go all the way to the floor, or can you see in it all the way to the floor?

The fact that they did a reno is suspicious. I would call an experienced plumber, pay for it, and bill the responsible party when the source is discovered.

Is the cutout in the wall still out, so you can look in there when they are home? Does it go all the way to the floor, or can you see in it all the way to the floor?

The fact that they did a reno is suspicious. I would call an experienced plumber, pay for it, and bill the responsible party when the source is discovered.
The cutouts are still there but they are not at floor level. I can only get my fingertips on the slab in one place. It is difficult to feel moisture as the slab is cold. They have been instructed to keep their cutouts open and their vanity was removed by the plumber not sure if that was put back. We are going to keep our main shut off for a few days, see what transpires then get a different plumber. Thanks for your help. If you think of anything else please please let me know. I will post an update after a few days of no water usage in my unit.

Hi Water Weary

Now that you answered Tom's question, "Can you confirm that this is a first-floor leak?" (I can only get my fingertips on the slab in one place), we can ask you some more questions... ;)

Can you tell us if there are any water pipes that go into the slab?

How about any heat pipes... any chance they go into the slab flooring?

Finally, after a 3rd visit from a plumber and you have no final result, as Joypulv kind of suggested, I would call the owner of the plumbing company you've been working with or call another plumbing company in and get them to look at the issue... should really not be as difficult when real professionals are brought into the job!

Back at you...

Mark

Hi Water Weary

Now that you answered Tom's question, "Can you confirm that this is a first-floor leak?" (I can only get my fingertips on the slab in one place), we can ask you some more questions...;)

Can you tell us if there are any water pipes that go into the slab?

How about any heat pipes...any jchance they go into the slab flooring?

Finally, after a 3rd visit from a plumber and you have no final end result, as Joypulv kinda suggested, I would call the owner of the plumbing company you've been working with or call another plumbing company in and get them to look at the issue...should really not be as difficult when real professionals are brought into the job!!

Back at you...

Mark

Sorry for my confusion!😊 Yes there are water pipes for all units through the slab.
No heating pipes, thank goodnes that is forced hot air.
Going to call management company to deal with this apparently inexperienced plumber that was hired by them!💲💲
The water main to my unit is still shut off and after one night there is still some water.
One more question for how many days should I keep the water off to eliminate my unit from this seepage?
Thanks and I am sure I will have more questions!😊

Open a valve closest to the main to see if your main is 100% shut off (if old it might not).
Open all faucets/spigots/tubs etc to make sure no water is standing in pipes and slowly leaking.
Take a video of opening the valve if you can, to show nothing is coming out.
If you can't, see if another neighbor can be a witness for 5 minutes of valve opening.
No need to leave it off after you prove no water is coming from your condo.
I'd be at the stage of suing somebody over incompetence.

Open a valve closest to the main to see if your main is 100% shut off (if old it might not).
Open all faucets/spigots/tubs etc to make sure no water is standing in pipes and slowly leaking.
Take a video of opening the valve if you can, to show nothing is coming out.
If you can't, see if another neighbor can be a witness for 5 minutes of valve opening.
No need to leave it off after you prove no water is coming from your condo.
I'd be at the stage of suing somebody over incompetence.
Thank you!

Thank you!

Thanks for the video suggestion. I had started taking pictures but the video would better.
24 hours now since shutting off main. This home is only 6 years old so no water coming through any open faucet, thank goodness!
There are new wet spots when paper towels are under the molding. Hoping this is not still residual seepage.
This is beyond fustrating, but having guidance from all of you makes me MUCH more informed.
It will be interesting to see what the original plumbing company will have to say 9 hours of labor later and still no answer on their part!
Kudos to all of you. Keep the advice coming! I will definitely be in touch😊

Are there any mechanical rooms nearby, or above the wet area? You mentioned forced air heating, which usually means there is central cooling; every air conditioning unit produces condensate, which must drain somewhere, either by gravity or pump. Is it possible there is an overflowing condensate drain...

Poorly insulated refrigerant piping, and uninsulated ducts will also attract & shed condensation.

What about a pressure test on the water supply piping? Attach a pressure gauge on the cold water piping, after your main shut - off valve, and let it sit overnight. Do the same thing in your neighbors home.

A peppermint test on the DWV piping will determine if the drain, waste, & vent piping are responsible for the leak... -.--

A peppermint test on the DWV piping will determine if the drain, waste, & vent piping are responsible for the leak.......-.--

No mechanical room near or above the seepage location .
The seepage was present prior to turning on the central AC. That can rule out the condensate issue ? (I hope!)
Can I get pressure gauge at any hardware store? My "neighbor" is no longer even looking at me. So unfortunately I doubt they would test their side.
Not sure what a peppermint test is. Dye was placed in mine and my neighbors toilets on different days. How do I know if enough dye was used to rule out the possibility of a problem in that direction?

No mechanical room near or above the seepage location .
The seepage was present prior to turning on the central AC. That can rule out the condensate issue ? (I hope!)
Can I get pressure gauge at any hardware store? My "neighbor" is no longer even looking at me. So unfortunately I doubt they would test their side.
Not sure what a peppermint test is. Dye was placed in mine and my neighbors toilets on different days. How do I know if enough dye was used to rule out the possibility of a problem in that direction?

New 3rd generation master plumber was here yesterday. My walls are open and toilet off . Water main back on. Slab under linoleum wet this morning after we had dried it out . He believes it is coming from the next unit . He did not enter their unit, unhappy neighbor. We are probably going to remove linoleum today at some point. Do you think that will give us a clue? The floor shoe molding that was removed had the most mold present in the corner section. Thanks for your continued help.

I'm not so sure about the benefits of a search using demolition as the first diagnostic tool. Why not start with a visual survey, looking for an obvious source of leak. My next step would be to define / identify all possible contributors, including a written log of where, when, how much water is showing up, & then begin an orderly process of elimination. A domestic water piping pressure test would be my next step, including testing the piping in adjacent properties, and if the pressure tests hold, I would do a peppermint test next, this will confirm the integrity of the dwv system...

We HAVE determined that this is a drainage leak and not a pressure leak, Correct? If so then Mikes peppermint test Would be a waste of time since you already know you have a leak. The only way I know of getting at and repairing the leak would be to open up the slab and locate the leak. Good luck, Tom

We HAVE determined that this is a drainage leak and not a pressure leak, Correct? If so then Mikes peppermint test Would be a waste of time since you already know you have a leak. The only way I know of getting at and repairing the leak would be to open up the slab and locate the leak. Good luck, Tom

Thanks for the good luck wishes, we need it! With our water main shut off and all pressure removed from pipes we still had water. This was for 3 days. We have lifted linoleum and are about to take it up completely along with removing the vanity. It has to be replaced anyway. We have kept a log of our usage and checked from the attic down to the slab for other signs of water. We have seen none . If the neighbors would do the same this would easier!😊 So any hints on how to remove the vanity are appreciated! First attempt at this type of thing! THANK YOU all again for your continued help.

I don't see where you have much choice. To repair the leak you must open up the slab and locate it. While the water may be coming from your neighbor in a common drain the leak is in your unit. Bite the bullet and opened the slab . Let me know how things go . Best of luck, Tom

I don't see where you have much choice. To repair the leak you must open up the slab and locate it. While the water may be coming from your neighbor in a common drain the leak is in your unit. Bite the bullet and opened the slab . Let me know how things go . Best of luck, Tom

Thanks again! Fingers crossed I will let you know...