Yes, a sewer inspection before buying a house is worth the cost, because a standard home inspection does not include the sewer line. The pipe becomes your responsibility the day you close, and a failed line can cost thousands to repair, so a camera check gives you that information while you can still negotiate.
The reason comes down to what a home inspection actually covers. The standards that home inspectors follow, such as InterNACHI’s, do not require the inspector to look inside buried pipes, so the lateral line running from the house to the city main is left out. A general inspector can flag slow drains inside the home but cannot see a crack, a sag, or root intrusion underground. A sewer camera inspection is a separate service that sends a camera down the line and shows its real condition.
Two things raise the odds of a problem: the age of the house and the trees around it. Homes built before the 1980s often have cast iron or clay pipe that corrodes or cracks with age, and mature trees send roots toward the joints in a sewer line. A camera inspection is not always necessary, though. A newer home with modern pipe and no large trees nearby is far less likely to hide a costly fault, so the check matters most on older lots.
If the camera finds damage, you learn it before closing, while you still have room to ask the seller for a repair or a price reduction. That leverage disappears the day you sign. For how the pricing works for buyers and when the check pays off, the pages on sewer scope inspection cost and whether a camera inspection is worth it cover the numbers.