We've had a bad odor coming from a bathroom on the 1st floor every since we moved in. In fact, I'm pretty certain the prior owners were having the same issue because I recall there being a lot of air fresheners in that area of the house when we were looking at it. In any case, I've replaced the wax seal myself twice. I also had a plumber come out, and he said it was a wax seal, so he replaced it a 3rd time. The smell persisted though. I went in the crawl space to see if I could see any sign of smell or dampness on multiple occasions, but nothing. I now think its a vent problem. I went up in the attic and found that the vent comes up to the level of the rafters to a 90 degree bend, it then courses over about 4ft in a horizontal plane, then it takes another horizontal 90 degree bend for another 4ft or so, then it takes a final 90 degree bend and exists through the roof. Does this sound like correct plumbing? It seems to me that this is a perfect "trap" for debris to clog the vent. We've thought off and on that the smell might worsen a little after rain, which I think would contribute to this theory. Any thoughts? Thank you!