While sewer lines can last for decades there are a number of factors that determine their overall lifespan. Old age, the sewer pipe material used, the environment, and accidents involving your pipes or drains all contribute to when you might need a sewer line replacement. Some signs that your sewer line is clogged or you may be in need of a sewer line replacement include, constant clogs, water pooling in your drains, or weird noises such as gurgling sounds coming from your pipes or drains.