The cesspool is the forerunner to the modern septic system. Before the advent of the modern septic system household waste was routed to a covered vertical pit dug into the earth called a cesspool. The pit is lined with a porous cement, or block, or stone. The area outside the liner is filled with gravel. All the wastewater from the home is routed there. The solids fall to the bottom where they are partially digested by bacteria and microorganisms that occur there naturally. The effluent leaches out into the gravel and soil surrounding the pit.
A cesspool, like a modern septic tank, must be pumped periodically depending on its size and the size of the household using it.