Maintenance of both the sewage network and all types of domestic and industrial pipe installations is practically impossible without CCTV inspection. Often you can’t solve a problem if you don’t see it or you’ll waste a lot of time.
Cameras are widely used by companies that deal with the installation and maintenance of ventilation systems, chimney maintenance, well maintenance, etc… Practically wherever it is not passable or safe for people to enter, cameras solve or make the job easier.