During the hydro-milling process, water is pumped high pressure through a self-propelled high pressure nozzle engineered for pipe wall cleaning at service pressures between 5000 and 12000 psi. The attached hose is then sent through a bi-directional feeder and rotated at operator-controlled rates into the piping. The rotational motion of the hose allows the nozzle to easily negotiate 90* elbows, piping turns, and directional changes, in addition to providing full surface area cleaning throughout