Septic tank
In the United States, the 2007 American Housing Survey indicated that about 20 percent of all households rely on septic tanks, and that the overwhelming majority of systems are located in rural (50%) and suburban (47%) areas. Indianapolis is one example of a large city where many of the city's neighborhoods still rely on separate septic systems. In Europe, septic systems are generally limited to rural areas.
Effluent sewer
Another problem area is a place where there are many homes or businesses at or near the lowest elevation in the area, such as sea level for a coastal city. Typically, waste is pumped uphill under low pressure to the main sewer line in such situations, either after it has been through a septic tank or after it has been ground up into a slurry by a grinder. Grinding can be done when the waste of many homes or businesses is combined or smaller grinders can be installed at each home or business. A disadvantage of using grinders is that they require electricity, and a disadvantage of using septic tanks is that they require solid waste buildup to be removed every one to three years, depending on the size of the tank and the number of people using the system.