My Grandparents had a septic system that lasted over 40 years and it was still working fine when the tank finally rusted completely through, a few years ago. I dont remember it being pumped out in the past 25 years...
She claims it lasted that long because of two things.
They always use only white toilet paper and they flush a package of yeast down the toilet once a month...
The guy that installed our new septic system recommended the yeast bit too. He’s reliable and trustworthy so I don’t think he’s pulling our leg. It’s way cheaper than Rid-X too. We are also judicious on our water usage too. Just cuz. Also, make sure you don’t have any trees or shrubs near your leech lines. We had a *really* *gorgeous* Hibiscus shrub in the yard. Before we knew exactly where the leech lines went. Guess why it was really gorgeous? Roots clogged up the leech line about 10 ft from the tank itself. Yucky isn’t even close. Our system is MUCH happier now!
We get the ginormous packs of yeast from SAMs and pour about 1/4 in the tank each month. Keep the rest of the yeast in a mason jar in the fridge.