The purpose of flushing and jetting which is what we do in Drayton Valley is to clean and remove blockages in the sewer lines.
Flushing introduces large volumes of water into a manhole which is effective for removing floatables and some sand and grit from the lines.
Jetting, which is what we do in Drayton Valley, directs high velocities of water against the pipe wall, this removes debris and grease build-up, clears blockages and even cuts roots within small diameter pipes. This is efficient for routine cleaning of small diameter pipes and low flow sewers.