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.
Indian River Lagoon
In 2016, there were an estimated 300,000 septic tanks in the five-county area bordering the Lagoon. At one time, sewer plants were worse polluters. In 1986, there were 46 sewer plants along the lagoon. They discharged about daily into the estuary. The state ended most sewer plant pollution by 1995.
In 2018, lagoon health is better near ocean inlets. Pollution is worse in areas near no inlets, such as the Mosquito Lagoon, North IRL, and the Banana River.