Look into installing a trap. In older homes fixture traps aren't always up to code and allow air to flow freely through the waste pipes.
Your septic system could be backed up and that is why you are smelling a foul smell. The best thing to do is to call a septic system business and have them come out and take a look at your septic system, if you think that is what is causing the foul smell.
Unplug the pipe between house and septic tank first. Get flow of septic into the tank.
you have a shower
check or have a plumber check p trap in drain line under shower. if leaking [losing water] it wont stop sewer gas from coming up the drain. probably the most likely cause.
Yes, -but the tank is filling up and will soon overflow starting at the lowest toilet. Much easier to service or replace your septic pump .
The sump should work as long as you have a strainer in the shower
Tank is full. Lid is not sealed.
take a shower!!!!!
Because they don't shower.
by taking a shower......you stupid
Yes, because you smell.
Because he doesn't shower