There is no definitive answer to this question as it can vary depending on a number of factors, including the type of material your sewer line is made from, the age of your home, and how well it has been maintained. However, most experts agree that the average lifespan of a sewer line is around 20-25 years. If you are unsure about the condition of your sewer line or suspect that it may be starting to fail, it is best to contact a qualified professional for an inspection.

It's impossible to give a universal answer, as the lifespan of a sewer line will depend on a variety of factors (e.g., material used, installation quality, soil type, climate, municipal maintenance). However, in general, sewer lines have a lifespan of around 50 years. So if your home is more than 50 years old, it's likely time for a replacement.