The ODOR is caused from the gases involved in the decay (Bacterial process of the waste Sewage surfacing in yard — Have tank pumped and reduce water usage. If problem persists, contact a Professional for assessment of problem. Inspection pipe caps damaged or removed — Replace damaged caps Vent on house not high enough to properly diffuse to odor — Increase the height of vent line. Diagnosing the specific causes may be difficult, and often requires the skills of a professional.