Roots usually return through the same cracks, separated joints, or damaged pipe sections that allowed previously-cleared roots to gradually enter the pipe in the first place. Hydro jetting with a rooter-class jetter and nozzle combination can clear root-intrusion blockages to restore sewer/drain flow, but rapidly-recurring root-blockage problems typically indicate that the pipe should be internally patched, re-lined, or replaced. 

Electric “mini” jetters simply do not have the GPM / PSI output to drive even the smallest root-cutting nozzle which requires at least a 4-GPM jetter with 3000-4000psi capability to cut out roots. Further, the best root-cutting nozzles (e.g. Warthog, Reaper, Rotodrill) all perform best when “fed” with at least 7-GPM at similar pressures from a larger gas or diesel powered jetter, which can provide the nozzle enough GPM+PSI “horsepower” to attack tough blockages.

Penetrating nozzles might be able to punch through a root blockage to restore flow quickly, but they have no ability to cut the mass away from its taproot to clear the mass from the pipe. While this can be a useful way to decant the line so that you can do a camera inspection of the pipe, leaving roots behind means leaving an obstruction behind that can easily cause another backup.  Rotating root-cutting nozzles are used to remove the entire root mass from the pipe, providing a fully cleared path for sewer/drain flow.

Rotating root cutting nozzles are typically the best option for heavy root intrusion because their sharp water-jets are rotated slowly to create a “slicing” and “tearing” action that chews into root masses. Many jetting pros first use a rotating Reaper or Rotodrill “coring” nozzle to chew through the roots to restore sewer flow, then follow with a rotating Warthog or Bulldog “scouring” nozzle if needed to clear any remaining roots that the coring nozzle might have missed.