We are on a septic tank system. We noticed a few weeks ago a very foul sewer smell coming from the closet in our upstairs bathroom. The pvc piping goes through this closet up to the attic and to the roof. My husband did see a link in the attic which was covered by duct tape and he fixed it with joint or whatever it is you call them. Anyhow, we can't find any visible leaks. What do you think could be causing this foul smell. It seems to be getting a little worse and lingers 85% of the time.

You probably have a leak behind the wall somewhere. You might want to hurry and get an expection.. it will be costly, but that type of stuff is really unsanitary... we once had a leak under the house, our neighbor and I share the septic line under the ground.. every time either one of us flushed the toilet it came up into our bathtub... it was horrible.. please do hurry before it gets worse!