Sewage odor eminating from 1st floor bathroom/laundry room
Hi and thanks for reading!
I own a two-story house in southern Michigan, with full basement, 2 1/2 bathrooms and a laundry room. House is three years old (finished Oct 2004).
In the past year, we have been getting raw sewage odor eminating from the 1st floor bathroom sink and utility sink in the laundry room. All plumbing in the house converges into a 3 1/2" outlet pipe to the local sewage lines in the basement.
I checked the traps, they've got water. What I can't find though, is a vent pipe! Having done some reading here on the forum, I conclude that a vent pipe should be running off the main drain line, through the house and out the roof, correct? Also, the trap in the bathroom has a local vent just before the down bend (charcoal filter). I'm considering removing that vent and capping it off.
Running water through the sinks usually (not always) gets rid of the odor, but that's expensive and wasteful.
What should I be looking for, and how to fix?