A cleanout is a point in the drainage system whereby drain cleaning can be performed such as snaking out the drain. Cleanouts are usually a fitting with a plug or cap for removal but a fixture's trap is also considered a cleanout in plumbing codes. Cleanouts are required at certain intervals and at changes of pipe direction.
A cleanout is used to clear stoppages in drain lines. In most cases, these are located outside, between your home and the city sewer or septic tank. Some smaller drains will also have cleanouts.
