OK, this is personal, not an inspection. Septic system for 2700 sq ft home, three bathrooms, two levels.
While my wife was taking a shower this morning I noticed the toilet bubbling( (bubbles coming from the drain). later when I flushed another toilet in the house, the sink closest to the toilet gurgled (apparently air backing through the trap).
Is this a waste vent problem or a septic system drain problem.
Any help would be appreciated.