odor from drains
We have 2 bathrooms, which share a wall. I've been noticing, on and off, a sewer-like odor from the sink drain. Sometimes it's quite strong, sometimes it seems to be there for a day or more. Then it's gone. This has been happening for months. I started smelling it from the shower drain now, as well. I think I smelled it faintly from the second bathroom recently, but only once. That may have been coming through the wall, however. The house is on a cement slab. The drains work fine. Any thoughts?