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.
Filling station
Most filling stations are built in a similar manner, with most of the fueling installation underground, pump machines in the forecourt and a point of service inside a building. Single or multiple fuel tanks are usually deployed underground. Local regulations and environmental concerns may require a different method, with some stations storing their fuel in container tanks, entrenched surface tanks or unprotected fuel tanks deployed on the surface. Fuel is usually offloaded from a tanker truck into the tanks through a separate valve, located on the filling station's perimeter. Fuel from the tanks travels to the dispenser pumps through underground pipes. For every fuel tank, direct access must be available at all times. Most tanks can be accessed through a service canal directly from the forecourt.