A cesspool is generally seen as a murky, dirty pool of liquid and partially dissolved solids. More specifically, the term is used to describe an outdated component of a septic system, typically replaced by a septic tank. Cesspools are inefficient and potentially hazardous but can still be found in some homes that don't have updated septic systems. Cesspools are comprised of a large subterranean hole, lined with pieces of rock or concrete, and covered with a concrete lid to protect it. Frequency of cleaning will vary depending on the size of the cesspool and how much use it gets.
Clean the cesspool by pumping and draining it. This is accomplished with a large truck with a tank and a suctioning hose. Pumped cesspools should be completely drained of both liquids, solids and "sludge" -- the term reserved for partially dissolved matter.
Alternatively, treat the cesspool by aeration. The aeration process involves dissolving the chemical sulfuric acid into the liquid in the cesspool. This breaks up the sludge and solids, allowing air to pass through and the liquids to dissolve on their own.
You can also clean the cesspool using hydro-jetting. Hydro-jetting forces water into the earth below the cesspool, which breaks up the liquids and sludge that are congealed at the bottom of the cesspool, preventing dissolution. This process quickly and efficiently allows the cesspool to return to normal, safe levels.
Treat the cesspool with caustic soda after pumping, aerating or hydro-jetting. This treatment opens up the tank of the cesspool, allowing the liquids and sludge to seep naturally. It also works to break down the grease and soap scum that can build up in the cesspool, coating the tank's walls and floor and preventing seepage.