Septic tank
A septic tank is an underground chamber made of concrete, fiberglass or plastic through which domestic wastewater (sewage) flows for basic treatment. Settling and anaerobic processes reduce solids and organics, but the treatment efficiency is only moderate (referred to as "primary treatment"). Septic tank systems are a type of simple onsite sewage facility (OSSF). They can be used in areas that are not connected to a sewerage system, such as rural areas. The treated liquid effluent is commonly disposed in a septic drain field which provides further treatment. However, groundwater pollution may occur and can be a problem.
Emerald Lake Hills, California
Emerald Hills used septic tanks until the early 1980s, a factor that limited building: In 1982, the year the sewer system was installed, the neighborhood had 900 homes. A building moratorium from the late 1970s to 1986 forestalled the boom—but by 1992, the count had boomed to 1,400, eliminating most of the vacant lots. Many of the new homes were large and expensive. Among the new residents were several Forty-Niners, including Joe Montana, as the team was then training in Redwood City. Today, only a few lots remain open, and though building of homes continues, most of them are on the sites of former cabins and vacation homes.