"F. Phillips hit the nail on the head! If you're in Maine, it's November, it's cold, the vent pipes for the plumbing sometimes get clogged with ice from condensation. If it's been cold & dry, the water in the sinks, tub & washer vapor traps evaporates a little quicker than normal. You may also notice the pipes & drains making an unusual noise when one of the vapor traps dries out. Pouring water into all drains will reestablish the "vapor trap" & the smell will stop entering the living spaces.
By F. Phillips (Guest Post)
11/01/2008
Check the vent pipes on your roof. They could be plugged. If they are plugged, odor will come out the drain or toilet.
By Jesse (Guest Post)
10/28/2008
My friend told me that a mixture of vinegar and baking soda works as good as Drain-O, and it takes the odor away. I haven't tried it myself, but it's worth a try.