Service to clear a clogged main line that was flowing out of the top of the cleanout in basement. Inspected and determined that main line was completely clogged; and observed paper towels coming from the opening of the house trap. Cleared main line with mechanical snake and pulled out more paper towels. Blockage cleared to sewer. Checked line with camera and all was clear. Spoke with owner about the cast iron lines in the area of the trap that were observed to be backpitched and had holes in them causing sewer waters to drain out onto floor in basement. The water were being removed by a sump pump located in that area. Additional estimate provided to customer for proper repair of the rotted/leaking cast iron pipeline.