Bathroom drain smell

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S Kimmel

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Hello All,

I am having an issue with my bathroom shower which is smelling like gases from the sewer each time I take a shower. I am a DIYer and I have attempted to remedy the issue with adding a air admittance valve after the p trap. This however did not work. I am posting the origin picture of the plumbing with the water route highlighted. Additionally the plumber who installed the line got out of the business and I have not been able to reach him for over a year. Any advice is welcomed.

~Stuart
 

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Diehard

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Hello All,

I am having an issue with my bathroom shower which is smelling like gases from the sewer each time I take a shower. I am a DIYer and I have attempted to remedy the issue with adding a air admittance valve after the p trap. This however did not work. I am posting the origin picture of the plumbing with the water route highlighted. Additionally the plumber who installed the line got out of the business and I have not been able to reach him for over a year. Any advice is welcomed.

~Stuart
You say each time you take a shower. Does that mean it doesn't smell after taking a shower?

A plumber installed that trap we see for the shower?
It appears that the shower trap could be violating the 24" maximum vertical distance allowed below the fixture it is serving. The idea being that a column of water of over a couple of feet could have enough momentum to carry through a trap. Of course that would be more apt to happen when releasing a larger volume of water all at once, like from a tub. I wouldn't think the low rate of flow from a shower wouldn't do it.

Is that a vent coming off the top of that 3" drain every thing is dumping into?
 

S Kimmel

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Yes the smell continues after taking a shower.

Yes a plumber installed the trap.

The trap middle measures about 24", bottom appears roughly 25" - 26".

The shower above has three 1/2 supplied shower heads and the smell persists using just one shower head.

That 2" pipe provides both a lavatory sink and the venting to the system.
 

Diehard

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Well it doesn't seem likely that the theory about a column of water clearing the trap would apply.

So I take it that the smell dissipates after awhile. If the trap remained open it would smell all the time, right?
In other words do you think the gas enters that area while showering or possibly keeps coming out? (Just trying to figure out this puzzle and looking for more pieces.)

So you have a 2" wet vent coming from lav sink. Does that vent go thru the roof.

Is this a new shower? Or a new problem with this shower?
 

S Kimmel

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Yeah the smell does dissipate after a while, and I completely follow you about it being open and smelling constantly. Just to be sure I smelled the drain and it wasn't present.

I have never checked the other drains while the shower has been on.

Yes the vent does go through the roof.

Its a new shower about a year or so old.
 

Diehard

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So is this a relatively new problem? I have to check out til tomorrow.
In the meantime maybe someone can come up with some ideas.
 

S Kimmel

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I would say that I recognized it a while ago, but I guess I put up with it as it does not smell the room up constantly.
 

S Kimmel

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I believe the tub is vented from the same location as the rest of the system through the wet vent in the kitchen sink.

Yes the tub was installed at the same time as the shower.
 

Diehard

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I don't know!
Nothing I see looks very good. I keep thinking that a DIY'er was involved in all of this piping.
Even that wet vent doesn't look correct. I'm sure some experienced plumbing will speak up and offer some input on this.
The thing is, right or wrong, it doesn't seem logical to be getting the sewer smells coming from the shower trap while in use and dissipate afterwards.
 

S Kimmel

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There is a slight bend in the pipe before it hits the bottom of the trap, so looking down from the shower I can not see the trap.

I would agree that this doesn't seem to be the most logical setup and most likely requires more venting, just not sure where to put that as it is covered up at the moment.

It does seem rather odd that I get the smell "some" of the time.
 

Jeff Handy

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Do you ever use the tub?
Maybe the tub trap has gone dry?

Yes, it would be a little smelly all the time, but would get a lot stinkier when you are flooding the shared stack with hot shower water, which could then greatly increase the stink output through a dry tub trap due to the chimney effect of the warmed up stack.
 
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S Kimmel

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I would say we use the tub every two months, but less in the summer. I will send some water down it to fill the trap and see if there is any difference this week.
 

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