There are many opinions regarding this question. I am in agreement with the theory of having your septic system pumped every two years. I would even go so far as to recommend that you have your drain field lines and distribution box flushed and vacuumed ever five years. The extra prevention and maintenance goes a long way toward saving you money down the road.
It’s also important to inspect the parts of your tank, such as the baffles, and the condition of the tank, including the covers. When I have my system pumped every two years, I add four gallons of Septic Drainer directly in the outgoing line to the drywell. We’ve lived in our house for 19 years and have not had any septic issues. The cost to replace my system would be over $20,000, so it’s well worth the extra maintenance. Take my advice and you will see the same benefits.
As far as the biological health of my system, I add our product Bio-Septic Boost. Approximately 2.5 ounces a month right in your toilet is all it takes. Bio-Septic Boost reduces organic waste material, including a byproduct of hard pan soil called bio-mat.