Nothing lasts forever, and your sewer line is no exception. Depending on how old your home is, the earth above your sewer line may have broken it or it may be made of old materials. Or some mixture of the two. Most sewer lines are made of strong, long-lasting plastic these days, but that wasn’t always the case.
Pipes in older homes are often made of cast iron or clay. Over time, these materials may break down and wear down until they break or even fall apart. When your sewer line breaks, the sewage it processes can’t go anywhere, so it backs up. If you’re worried about your sewer line, you can have a professional plumber do a camera inspection of your pipes to check their condition.