You say that the smell comes into the house. Does it come in from the laundry room (if upstairs) or out of the basement, or?. Do you have floor drains in the basement that are dried out and need water added to make their trap effective? It could be a clogged roof vent. How long has this been going on? As long as you have owned the house or did it just start? Are you on a septic system or city sewer? If you can't troubleshoot and provide specific answers, I would suggest you have a plumber stop by to offer suggestions. Please Respond, Dodgeman