Water is piped to some homes from a public supplier.
At other homes, people provide water for themselves from sources, such as a well, a cistern, a pond, or a stream. Water leaving our homes generally goes either into a septic tank in the back yard where it evaporates or seeps back into the ground, or is sent to a sewage-treatment plant through a sewer system. That is, it was evaporated or transpired from yards. The other 74 percent was discharged to septic tanks or sewage-treatment plants, where it was cleaned and sent into streams, or sometimes reused for other purposes, such as watering golf courses and parks. Estimates vary, but each person uses about 80-100 gallons of water per day.