Ours does that sometimes. With ours it was the drain trap getting dry. We find that if we just run a little water in each sink and shower it stops the smell.
We use to have a washer/dryer and the drain hose was too long. We pulled it out and cut about 6 inches off and it stopped sucking dry.
Good luck. Last resort.... couple of clothespins on the noses might work. haha
Ginny & Eric - Full Time 4/14/12 - Our Blog "Walk About With Wheels"
2004 Winnebago Vectra 40AD - 350 Cummins ISC; Toad 2012 Wrangler 6 speed
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