My first post and I will try to include all pertinet info.
House built early 50's and sewer outlet is above basement floor approx 12".
Installed basement full bathroom with shower, toilet, and sink new with sump system to pump into main cast stack and out to city sewer system.
The system is independent from all upstairs plumbing. Check valve also installed to separate upstairs from down.
Piping and sump system installed under concrete floor then patched, tiled, etc.
When sump pump engages, a strong sewer gas smell permeates the basement then the rest of the house. The smell does not occur every time, only sporadically.
System was installed by qualified contractor and double checked by another qualified tradesman who could not find any workmanship problems.
Venting has been checked.
All piping checked for leaks, cracks etc... needed to cut access holes in drywall to access lines and vent lines.
Anybody....any ideas please....the system is almost unusable at this point.