Sewer Smell Under Kitchen Sink

[Formosa]

My house was built in 2011 when I bought it new. I started having sewer smell coming from under the kitchen sink cabinet about 3 years ago. No smell from the sink or dishwasher. I deep clean them regularly. I also don’t have food debris in the dishwasher.

I can’t figure out where the sewer smell is leaking from but I smell it when I open the cabinet. I did the following.

1. Replaced the dishwasher drain hose
2. Painted the underside of the sink with some kind of sealer paint ( I read that the undercoating can smell bad)
3. Replaced the AAV valve
4. Covered different parts of the pipe joints and the entire AAV to see if that’s the leaking point. (failed to find it). I don’t have water leak there but I gave it a try anyway.

Is there any possible causes that I missed? Any suggestion is very much appreciated.

 

[rsoto]

It may just needs some kind of drain cleaner ran down the kitchen sink. I would try baking soda/vinegar and then pour down a pot of boiling hot water directly into the drain.

 

[TomFOhio]

Hi rsoto, welcome to the plumbing site. Good advice you gave him. The only thing that I would do
different is use the hottest water you can get out of the faucet. The only reason I say this is I have
seen what boiling hot water can do to the plastic tubular piping. It can warp it really bad.

 

[rsoto]

Hi rsoto, welcome to the plumbing site. Good advice you gave him. The only thing that I would do
different is use the hottest water you can get out of the faucet. The only reason I say this is I have
seen what boiling hot water can do to the plastic tubular piping. It can warp it really bad.

thanks!

it can? I was under the impression pvc can handle really hot temperatures. Good to know.
I also like to add is to avoid grease/oil going down the drain. Any meat dripping and old frying oil should be in a jar and thrown away in a trash. Especially bacon grease.

 

[JG plumbing]

Have you pulled that cleanout cover off and checked the threads?

 

[Formosa]

It may just needs some kind of drain cleaner ran down the kitchen sink. I would try baking soda/vinegar and then pour down a pot of boiling hot water directly into the drain.

Thanks for the comments. I did the baking soda/ vinegar clean up several times already. There is no odor. It is not coming from inside the drain. It is from underneath the sink. Very odd.

 

[TomFOhio]

There could be a crack in the piping inside the wall. A test would have to be performed in order to find out.
Check all the pipes underneath the sink to make sure nothing is cracked. Fill both sinks to the top and then
let them both out at the same time and then check your pipes underneath while the water is draining.

 

[Jeff Handy]

Try installing a different aav vent.

 

[Formosa]

Have you pulled that cleanout cover off and checked the threads?

Do you mean the round stainless steel plate? Good idea. I just pulled it out and there is a hole. Do you know what that hole is?

 

[JG plumbing]

It's a hole in a threaded cleanout plug. Id unscrew the cleanout tape and dope the male threads. Seal it back up and then dope the screw for the cover to make sure it's sealed.

 

[TomFOhio]

If that plug doesn't seal then I would replace the plug and just put the chrome cover on with maybe
some two sided tape or something.

 

[Formosa]

Try installing a different aav vent.

I already replaced the AAV. You think the new one failed too?

 

[Jeff Handy]

Easy to change it again, to eliminate a variable.