To find the problem running in a sewer pipe we use camera (CCTV) with monitor beside to find the problem underground and locate the weak point to fix it later. You will be able to see the shift, broken pipes and roots infiltration to it. It is very important to make proper diagnose to prevent unnecessary repairs and re-installation to the sewer pipe, especially it is very important if the pipe has a damage and locate under the floor in the basement of the house.
Camera is very helpful when you are in a process to buy your house, check drain AS MUST! Save your money, save your time, let plumbers be on your side.