Effluent sewer
Effluent sewers also currently serve fewer people than septic systems, which also use septic tanks, but simply dispose of the effluent by draining it into a leach field. About one quarter of United States homes dispose of their wastewater with septic tanks. However, effluent sewers are being looked at as a sewage treatment solution in areas where gravity sewer systems are not well-suited or when the high capital cost to build a gravity system is prohibitive. Areas that are less than ideal for gravity systems include areas that are large, but extremely flat and areas that require long-distance pumping, such as where homes are widely spread out or when several small villages or towns connect their sewage systems so that a centralized plant can be built.
Cistern
Some cisterns sit on the top of houses or on the ground higher than the house, and supply the running water needs for the house. They are often supplied not by rainwater harvesting, but by wells with electric pumps, or are filled manually or by truck delivery. Very common throughout Brazil, for example, they were traditionally made of concrete walls (much like the houses themselves), with a similar concrete top (about 5 cm/2 inches thick), with a piece that can be removed for water filling and then reinserted to keep out debris and insects. Modern cisterns are manufactured of plastic (in Brazil with a characteristic bright blue color, round, in capacities of about 10,000 (2641 gallons) and 50,000 liters)(13,208 gallons). These cisterns differ from water tanks in the sense that they are not entirely enclosed and sealed with one form, rather they have a lid made of the same material as the cistern, which is removable by the user.