For hydro-jetting, separate the line, install a backflow preventer, begin with lower PSI, then increase as needed
https://city-wiki.win/index.php/Coming_From_Blockages_to_Clear_Lines:_Just_How_Hydro-Jetting_Improves_Septic_Tank_Maintenance
For hydro-jetting, isolate the line, install a backflow preventer, start with lower PSI, then increase as required, using proper nozzles to search biofilm, roots, and scale without hurting pipelines.