Dodgeman, the smell seems to be coming from the pipe where the washer drains. This is the only place we ever smell it. We live in a one-story house with no basement and are on the city sewer system. My husband bought this house when it was under construction about 25 years ago. The smell started a few years ago and I kept blaming the washer. About two years ago we replaced our old Maytag washer with a Maytag Neptune and the odor stopped. Unfortunately, it started again recently and the stench is overwhelming at times.
My husband tried drain cleaner with no success. Are the foaming cleaners good? He wonders if perhaps there is a film over the vent and the foam would expand into a possible problem area. Evidently, there are some "t's" that a liquid cleaner won't reach.
Bob, that's a good idea. I still blame the washer occasionally and wondered if it could be the problem. Might be worth a try just in case, especially since I'm afraid that if it's the vent, we'll have to start tearing out the wall!