For hydro-jetting, separate the line, install a backflow preventer, begin with lower PSI, then increase as needed

https://wiki-site.win/index.php/Septic_Tank_Pumping_and_Maintenance:_A_Homeowner%27s_Step-by-Step_Resource

For hydro-jetting, separate the line, install a backflow preventer, begin with lower PSI, then increase as required, using proper nozzles to scour biofilm, roots, and scale without hurting pipes.