Cesspools and tight tanks lack the ability to filter waste, and the sewage eventually contaminates the surrounding soil. The septic system has two essential parts: (1) the septic tank and (2) the soil absorption area. Any cesspool past its prime today would most likely be replaced with a modern septic system. Septic tanks and cesspools are two methods of disposing of liquid household waste in rural areas that do not have access to public sewer systems. Septic tanks are generally considered to be an improvement over cesspools.
A septic tank separates household sewage while allowing residual water to overflow out into a drain field or connected cesspool.
The septic tank is the primary component of the septic system, part of an elaborate distribution method which sends only the effluent (water) to a distribution box which has outlets for multiple perforated pipes. The modern septic tank is a watertight box usually made of precast concrete, concrete blocks, or reinforced fiberglass.