To start, hydro jetting is the process of high pressure water used to flush out a sewer system of buildup and debris. This process was originally made popular for industrial business where grease buildup over time would clog pipes. Primarily the restaurant business.
Over time, fittings for hydro jetting hoses were invented that specialize in removal of more solid debris like root intrusions.
The most common issue people can run into when deciding which hydro jetting company to hire is a lack of understanding that hydro jetting with a fitting designed to focus on the removal of grease is going to be very ineffective on something like root intrusions.