Hydro jetting keeps a residential sewer line clear for about one to three years, depending on what caused the buildup. Grease comes back as the household keeps sending it down the drain, often within a year in a heavy cooking home. Tree roots return fastest, because jetting clears the roots but does not repair the crack they grew in through.
This is about how long the results last, which is different from how long the job takes. The cleaning itself is done in a couple of hours. How long the pipe then stays clear is set by the cause, not the cleaning: a line scoured of grease can run a year or more, while a line near mature trees may need service closer to once a year.
Roots are the reason jetting can feel temporary. They enter through a crack or an open joint, and clearing them leaves that opening for the next season, so a city utility that rods root prone lines may do it as often as every six months. The lasting fix is to repair or line the pipe so the joints are sealed and the roots have no way back in.
The month figures are a guide, not a promise. Duration depends heavily on the pipe, the household and what is growing nearby, and jetting cannot stop regrowth where a structural defect remains. Where a camera shows cracked or root damaged pipe, repeat cleaning treats the symptom while repair treats the cause. Regular hydro jetting still has a place on lines that simply collect grease or scale.