Sewer smell after shower

[Luv2Q]

Hi, all ..

Have a small cabin with 1 bath, toilet, bath sink and kitchen sink.

Main drain is 3" with (a) 1.5" vent line from kitchen and (b) 1.5" vent line from bathroom. All run to a septic tank which is definitely downhill from the cabin.

After a shower or bath, the sewer smell is pretty strong. No apparent leakage from the P-trap under the tub, and vent lines seem open/unobstructed.

I can't think of where else to look to try to eliminate the smell.

Sure hoping you guys have some suggestions. Will be most appreciated! Daughter is getting pretty impatient!

[Redwood]

Are all the fixtures trapped?
Is the toilet loosely mounted to the floor or rocking?
Does the vent go through the roof?

[Luv2Q]

Redwood ..
Yes, all fixtures trapped.
Toilet seems mounted ok. Doesn't rock or leak, at least.
Vent goes thru endwall near peak then turns up to even with roof ridge.

Thx

[whitequeen96]

OK, I'm a Newbie, and this might seem very low-tech, but it worked for me. You mentioned this problem is in your cabin. Is this where you live all the time, or is it for vacations, weekends, etc? I ask because I have a sink behind my bar that I never use. After a while, it started to smell whenever I ran the washing machine right next to it. Someone told me that a kind of felt pad or something like that had probably dried out because of not using it, and this allowed the sewer smell to enter the house. All I have to do is run the sink occasionally, just enought to keep the pad moistened. This cured the problem right away. If your cabin is not used regularly, perhaps you could just leave the shower faucet on enough for it to drip and keep the pad moist. It certainly won't hurt to try! Let me know how it works out!

[Luv2Q]

WQ, thanks. I'm not sure where a felt pad fits in but my guess on your bar sink: If you don't use it for a long period of time, it seems like the water in the P-trap could evaporate which would open up the sink to smells coming from below the trap. Running the water every week or two for a minute would refill the trap.

My little "cabin" gets daily use so that's not our problem. Thanks for the suggestion, though.

[whitequeen96]

Oops! Well, that P-trap answer certainly makes more sense than a felt pad! (I did wonder about mold, etc.) I was just glad that running the water solved my problem. I hope you find an answer to yours!

[Redwood]

Any air admittance valves?

[Luv2Q]

Any air admittance valves?

Sorry, Redwood. No AAVs. Had 2 but removed them and teed into a single vent stack.