I have been inspecting homes in Northern Colorado for over 17 years and it seems that in recent years sewer scope inspections have become more and more popular as an ancillary service for home inspectors and has become a very common service for me to add to my inspections.
I can see why. A lot of sewer systems have defects, and they are not just old systems (clay, cast iron, and Orangeburg). I find defects and poor installation even in new construction where yards and driveways have to be dug back up for repairs. I had been recommending doing sewer scopes for years, but few clients actually did it. Now it is requested on about every other inspection. I used to subcontract out the work but learned how to do them myself have been doing a lot over the last 3 years. It has been interesting to see the inspection industry grow and change. I remember when nobody had heard of Radon or drones for a roof inspection.