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.
Cesspit
Before construction reforms were introduced in the early 19th century, liquid waste would seep away through the ground, leaving solid waste behind in the cesspit. While this made removal of solid waste easier, the seeping liquid waste often contaminated well water sources, creating public health problems. Municipal reforms required that cesspits be built of solid walls of stone and concrete. This kept liquid waste in the cesspit, forcing cesspits to be cleaned more frequently, on average two or three times per year. Liquid cesspit waste would be removed with pumps by cesspit cleaners, and then solid waste, valuable as fertilizer and for manufacturing ammonia, was removed. 
In 1846, French public hygienist Alphone Guérard estimated that 100 cesspits were cleaned in Paris every night, by 200-250 total cesspit cleaners in the city, and out of a total of 30,000 cesspits. The replacement of Paris' cesspit system was challenged for decades by officials not on public hygiene grounds, but on economic ones, based on the desire to conserve human waste as fertilizer rather than disposing of it in a modern sewer system. Paris' sewer system began modernizing in the 1880s, with the conversion of storm sewers for public sewage. Some cesspits were still in use in Paris into the 20th century.