Adding yeast to a septic system does not help waste degrade faster. Over-the-counter septic tank additives, while more expensive, also do not improve the operation of the system. Most septic tanks can handle up to a gallon of bleach weekly without disrupting the bacterial action.
Some septic tank additives cause environmental problems and groundwater pollution. Instead of attempting to avoid the inevitable need to pump the tank, an owner should have a professional inspect the septic tank every two years. If an owner waits too long to pump the tank, solids begin to spill into the drain field, causing further contamination. The solids also fill the vital air spaces in the soil and ultimately lead to system failure.