Attempted to clear a main sewer line blockage using a jetting machine. Inserted the high-pressure jetting nozzle into the 4-inch cast iron pipe through a two-way cleanout. Gradually increased water pressure up to 4000 PSI while monitoring flow and pull on the hose. Repeated jetting passes in both directions but was unable to fully restore flow. Recommended excavating and replacing the damaged section of sewer line due to root intrusion and pipe deterioration. Provided a detailed estimate for the sewer line replacement, including permits, landscaping, and surface restoration.