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.
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.