Sewage ejection pit emitting odours.
The Pit services a shower, sink and toilet, and is about 20 feet away from the main sewage stack. The odour occurs after the pump goes off, and the sewage smell lingers throughout the house for about 2 hours thereafter.

We'd had 3 different plumbers, our city's chief plumbing inspector, and various contractors on site trying to identify the root cause of the problem and none have found the cause.
We've replaced the seal a few times, have replaced the lid, have caulked all connections, passed pressure tests confirming the vent and lines are clear and sealed.

Any other ideas?

Does your ejector system have two separate vents? One dedicated vent for the pit that runs out the roof without connecting back to a house vent and another from the fixtures that is allowed to tie back to a house vent?
Regards, Tom

Thank you for your question.

The Sewage Ejector Pit vent connects to a PVC "T" connection, and the lower bathroom (toilet/sink/shower) vent appears to connect to this same "T" joint , and it all vents out through the main floor and attic via one vertical pipe.

(Note that there is a second vent system running through the roof from the main floor bathroom and kitchen but this is totally separate.)

Is this inappropriate construction and is there a simple process for testing if we are getting some back draft or something?

Thanks so much!

Hi Bren and Karen
Your problem sounds very similar to ours. I know it has been a few years for you now but I am curious to know if you were able to solve your problem and if so were you able to glean anything worthwhile that you could perhaps pass on to us?
Many thanks
Bron and Brian

Hi, your problem sounds very much like ours! Sorry to report ours has still not been resolved, continues to be worse in the winter or colder months (may be unrelated, but is a fact). The only added item we have changed is, through a soap test discovered there was a small air leak at a floor sewer line cleanout that was capped with a mechanical plug. We replaced the mechanical plug with the original cast iron cap, lining the threads with Teflon tape. Our odor now returns in a new location, seemingly the basement shower floor drain. Good luck, keep us posted if you learn anything. We continue to consider if the pump pressure creates a force that is too much for our existing cast iron lines in the original plumbing.