The close below one of our upstairs bathrooms is increasingly becoming filled with a strong sewage odor. We have had the sewage pipes cleaned out with no change of odor. The vents pipes seem clear as well. The odor is completely localized in this closed but it is getting stronger daily even if we do not use the upstairs bathroom.
COMMUNITY FORUM
Use the bathroom more often and see what happens.
If the traps dry out from lack of use (evaporation) the odor can come right in through the drains.
Otherwise investigate the vents for the sewer lines, might be clogged with bird nest or something.
Four possibilitoes. The vent stack inside the walls exiting the roof thru the attic is disconnected or blocked; A fan is drawing the vent gasses in from the outside; the wax seal on a nearby toilet is not properly seated on the floor flange (the trap on a toilet is inside the fixture, not in the drain lines; the odor is not sewer gas but a dead animal(mouse, squirrel, bird) inside the framing or attic.
