I just bought a new house and there is a septic odor that comes into my master bathroom. There has been no backflow and no other problems. Everyone I have talked to says they do not know what could be causing the odor since there is no backup type problem. I have checked to make sure that there are pee-traps on the sinks. When I called to have the plumber come out there was no odor on that day. The odor comes and goes and can last from half a day to a week. Does anyone know what I should try? Please, help