A septic system—or on-site sewage facility (OFFS)—is a method of dealing with household wastewater in areas where city sewer is not available. There are many types of OSSFs. Most people use the term “septic system” very generally, which may include all types of on-site sewage facilities. A typical standard septic system consists of a septic tank (to separate the solids from the liquids) and an absorption area where the liquids are treated in the soil before returning to the groundwater supply. Learn more about common septic system types, or watch a septic system animation.