# Mysterious odor in my bathroom near Vanity / Sink



## MountainLion (Jun 20, 2014)

I have this problem of a strange odor in my bathroom. In the following sections I provide additional details, including the troubleshooting I have done so far without any successful outcome. Any help will be very much appreciated.

*A) Problem Statement:*

Presence of a odor in the bathroom. I don't know how to explain or express the odor in words, but I'd call it musty. 

I am not sure if it is sewer odor. At first I didn't think it was. Now I am not sure any more. Sometimes it also smells like a damp, mildew kind of odor. I considered things like rotten wood smell, mold etc, but not having smelled any of those before I can't make a proper determination.

*B) Location of the odor:*

Strongly from the corner where the sink and vanity are installed. The smell also comes underneath the vanity when I open the door. But it is strong even when I don't open the door. It is present both when the sink is open with water flowing and when it is turned off.
Also the same kind of odor comes when the toilet is used (which is right next to the sink / vanity separated by about 90 cms)

*C) Additional details:*

The bathroom is on the second floor. It has windows that are open during the day time in summer months.
No mold or contamination in the vanity or underneath. Bathroom has exhaust fans installed recently (3 weeks ago). No wet clothes in the bathroom. The water drains well in sinks and no slow drainage of any kind. No bubble formations, gargling sound etc.

*D) Troubleshooting done so far:*

1) I used all kinds of liquid plumber (like drano etc) and that didn't help
2) I used bleach to clean the floor and other areas of the bathroom, that didn't help
3) Used vinegar and baking soda in the overflow drain. That didn't help.
4) Called a plumber to check the drain vent stack / pipe. He disagreed with my thinking and examined the fresh air vent. Though I disagreed with his suspicion, I allowed him to do whatever he wanted to do. He snaked the fresh air vent and that didn't help at all. I asked him to replace the P-trap underneath the sink (in the vanity) and that didn't help either. I spent a whole bunch of money and nothing I had the plumber do, helped solve the problem.
5) Removed the wall decorations, mirror etc, to inspect the wooden paneling behind. Re-sanded the wall, repainted, that didn't help.
6) Exhaust fan didn't help either
7) A contractor came with a device (a gun / driller kind of device that uses infrared or other means to detect dampness without having to cut out the drywall). He checked the walls, and the device revealed no water damage. 

*E) Suspicion (to be validated by experts in this chat room)*

1) Could it be due to some kind of loose connection at the "junction" where the drain system meets with the bathroom plumbing infrastructure?
2) Is it possible the drain vent stack is broken or rusted or misaligned in some way exposing a hole / gap of some kind?
3) Is it possible that the subfloor underneath the bathroom tiles is rotting ?
4) Is it possible the smell is traveling from elsewhere down the plumbing line?
5) Dead rodent or something stuck behind the walls ? If yes how do I locate / confirm it?
6) Any thing else you can point me to? 

*If a plumber and a handyman failed to find the source, how to I go about finding the root cause of the problem? Do I need to rip apart the walls, tile floor etc (the "sledge hammer" approach)? Is that the only option I have now?* :confused1:

Can I use homeowner's insurance for this? Is it a good idea to involve my insurance company at this stage? If not when should I involve them?

Any help is appreciated.


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## jmon (Nov 5, 2012)

Liquid plumber/drano isn't going to help and may make matters worse.

You seem to have pretty much cover all the bases. Bathrooms are notorious for this and can be hard to pinpoint the source. Do you have access from above and below or is everything finished? 

Stay tuned, others will be along with more suggestions/advice. Thanks.


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## yuri (Nov 29, 2008)

I suspect the plumbing stack where it attaches to the pipe where the sink and toilet drain into is cracked or come loose at that connection. Not sure what type of pipe you have or how old the house is. They used to use lead and oakum in some of those connections and maybe it is deteriorated or leaking. Sounds like a stack/venting problem if both the sink and toilet are doing it and it is above the water line of them. Pipes expand and contract with changes in temp and houses and walls expand/contract with changes in humidity so maybe it is leaking from age and movement.


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## TheEplumber (Jul 20, 2010)

How old is the house and what type of pipe do you have?

Have you looked under the vanity- toe kick area?

Have you pulled the toilet to check the sub floor for damage?


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## MountainLion (Jun 20, 2014)

*Access above & below*

Thank you for your response. I don't understand the notion of "access above and below". Above the bath room is the attic, and unless I take off the fiberglass insulation and dig near the edges, I can't look down from the attic behind the walls - isn't this typically the case? Asking because I am fairly new to DIY lifestyle. 

As for below, there is garage. So unless I dig through the ceiling of the garage, I can't get any insights.

Please let me know if I misunderstood your question. Many thanks again.



jmon said:


> Liquid plumber/drano isn't going to help and may make matters worse.
> 
> You seem to have pretty much cover all the bases. Bathrooms are notorious for this and can be hard to pinpoint the source. Do you have access from above and below or is everything finished?
> 
> Stay tuned, others will be along with more suggestions/advice. Thanks.


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## MountainLion (Jun 20, 2014)

yuri said:


> I suspect the plumbing stack where it attaches to the pipe where the sink and toilet drain into is cracked or come loose at that connection. Not sure what type of pipe you have or how old the house is. They used to use lead and oakum in some of those connections and maybe it is deteriorated or leaking. Sounds like a stack/venting problem if both the sink and toilet are doing it and it is above the water line of them. Pipes expand and contract with changes in temp and houses and walls expand/contract with changes in humidity so maybe it is leaking from age and movement.


Thank you. The house was built in 2001 - so about 13 years old.

I am not sure what kind of pipes are used, but to pursue your theory (which makes sense), how should I go about doing it? Rip the floor tiles and remove the vanity? I am preparing myself for that possibility (though wishing I will be able to avoid doing that), but want to confirm that's the only thing I could / should do. 

Assuming I may not be able to do the entire job myself, it will involve partly a handyman and partly a plumber - is this right? (with me doing whatever I can before leaving it to the experts)

Also it is interesting that you mention the word "leak". A contractor came with a gun (infrared I think) to detect any moisture / leak behind the walls, and he didn't find any. Does this rule out any leak? Are those devices reliable?


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## MountainLion (Jun 20, 2014)

TheEplumber said:


> How old is the house and what type of pipe do you have?
> 
> Have you looked under the vanity- toe kick area?
> 
> Have you pulled the toilet to check the sub floor for damage?


Thank you for your response, the questions and the interest to help.

1) The house was built in 2001 - so about 13 years old.
2) I do not know the kind of pipes out there. Never had an opportunity to check.
3) Yes I did look under the vanity. By this I mean, I looked under the sink in the cabinet kind of area. It is clean. I have some tools and solutions there. I removed the solutions to check if those were causing the odor, and that was not the case. That said, I didn't look "under the whole vanity assembly". I wanted to do that, but that would involve breaking the tiles near the toe kick area (as you used that term, assuming I understand that correctly). The vanity is sealed in the front and right side by tiles. Back and left edge are fused with the wall. Therefore for me to look underneath the entire vanity, I will have to break the tiles, and rip it off from the walls, and lift it up. Before I did that I wanted to check with experts like you in this chat room. Seems like you are suggesting that's the next step?
4) I have not pulled the toilet out either. I was reading about how to do that, watched some videos, but what is not clear to me is, even if I do that, how can I get a "broader look" at the sub floor underneath? The toilet sits on a small area and only a small gap will be exposed if I remove the toilet - right? I want to do this, but at the same time want to make sure this will give me enough of view into the sub floor underneath.

Many thanks again for your response and the offer to help.


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## yuri (Nov 29, 2008)

If the house is 13 yrs old it should be using PVC or ABS plastic pipe for the drain and venting. In the old days they used cast iron. It is possible one of the joints was not glued together properly or they may have used a MJ metal jacket clamp which is a piece of rubber with 2 gear clamps and it came apart. Glue is supposed to be used but depending on whether the plumber did the job properly etc is where the problem lies. I has a new house built in Calgary and believe it or not the guy did not tighten all the caps on the cleanouts. Guess he went around and dropped them on, screwed then in a bit and forgot to go back. Now if I did not tighten them or enclosed them then that would be a huge issue. Not sure what to tell you and it is a shame to have to open walls to physically look at that pipe. Unfortunatley with the housing boom or hacker builders this stuff happens. There are drain cleaning machines that have a camera on them so if you can find a plumber with one and willing to snake it down the stack then he may be able to see if it is separated somewhere. Rather than open walls I would try that.


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## TheEplumber (Jul 20, 2010)

Does your lav have an auto air vent or is it vented in the wall? AAV's can fail in the open position causing odors.

Pulling the toilet will allow you to examine the subflooring for damage. It's possible the toilet flange is set too far below the tile and water is seeping over the bowl wax and soaking into the plywood subfloor. You probably won't see damage by just looking at the floor- but it can put out a musty smell.

You can buy a small inspection camera on a flexible wand to look inside walls or under cabinets. This will minimize damage to finishes.

It's really hard to say what the problem is through a PC monitor- we can only offer suggestions based on our experiences. It may be a small water leak or drainage leak or even dead mouse....


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## Bud Cline (Mar 12, 2006)

TheEplumber said:


> Pulling the toilet will allow you to examine the subflooring for damage. It's possible the toilet flange is set too far below the tile and water is seeping over the bowl wax and soaking into the plywood subfloor. You probably won't see damage by just looking at the floor- but it can put out a musty smell.


 
That's the first place I would look especially if the floor is tiled. Pull the toilet, stuff a rag in the drain pipe, then sniff around a little and see if the same musty odor exists around the drain pipe. You may also discover loose tiles under the toilet pedestal depending on the size of the tiles.

Check the ceiling in the garage for water stains or loose seam tape.


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## Ghostmaker (Mar 2, 2013)

Pour ammonia down your vent stack on the roof. See if someone else notices ammonia smell inside the house. That person cannot be the one who dumps the ammonia.


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