I have my own summer cottage, and I’m sure that those who live in the countryside in private houses often face the need to have a septic tank. If you have such a system, you most likely pump it out regularly, perhaps even more often than twice a year. I will tell you how to minimise this need.
Why does the pit fill up so quickly? To understand the situation, it is worth considering the structure of the pit. Usually, it is dug out of the ground and lined with bricks. But with this design, liquid seeps into the soil, and solid waste blocks the space between the bricks, preventing normal drainage. This causes rapid filling.
After the next pumping, you should clean the walls of the pit and use specialised chemicals. However, the most effective solution is to install a septic tank with two concrete chambers. The first chamber serves to settle solid waste, and the second is designed to drain liquid into the ground. 
From my own experience, I would add that I planted three bird cherry trees next to my septic tank. These trees consume a large amount of water – about 200 litres each per day. Thus, they actively absorb 600 litres of water daily, preventing the pit from overflowing. Follow this advice and you will no longer have to clean your pit so often.
The builder shared a good tip so that the cesspool never has to be pumped out again