What is a sewer cleanout, and how would you know where to find it? As with any drain line, it is possible for your sewer lines to get clogged, even though the pipes are so big.
When this happens you have a potential disaster on your hands which can cause major damage, as well as, spread disease. A sewer cleanout is a location where you can access your main sewer line, possibly cleaning out a clog that has formed. Where you will find this pipe depends a lot on the weather where you live. If you live in a colder climate, then it is most likely inside of your home, near a toilet on the ground floor.
In warmer climates, it might be near the same location, but outside your home. Usually, the sewer cleanout is a pipe with a square peg on top of its screw-on lid. From this access point, you might be able to dislodge a clog with a snake.