We occasionally get a strong sewer smell in our basement. At times it would be so strong that we thoutht it was from bad seals around the toliets. We changed all of these but we still get the smell. It was more noticeable when we had guests and therefore more water was being used. However, recently it came again and there is noone here but 2 of us. any ideas?
We have had a similar problem and we think (hope) we now have it solved. We only get the smell when the leaves have fallen. We think the wind currents are pushing the gases from our vents up the roof and into the ridge vent into the attic. Once there, they work their way down a plumbing chase to our foyer. Our house is in a heavily wooded area on a north-south slope. If this helps please let us know.