Sewer Maintenance, Cleaning, and Rehabilitation
Core concepts
Know cleaning methods and when to use them: high-velocity jetting (hydraulic), mechanical rodding, bucket machines, and root cutters. Jetting is first choice for grease and debris; use lower pressure near fragile pipe. Know nozzle types and that you jet downstream-to-upstream cautiously to avoid pushing debris into laterals and to control backflow.
Rehabilitation
Cured-in-place pipe (CIPP), slip lining, pipe bursting, and spot repairs address defects found in inspection. Selection depends on defect type, diameter, and structural condition. Root intrusion and grease are maintenance problems; cracks, offset joints, and sags are condition problems.
Safety and traps
Confined space, traffic control, and high-pressure water hazards apply. Questions test whether you choose the right tool: roots need a cutter, grease needs jetting, and heavy debris may need a bucket machine. Do not confuse rehabilitation with maintenance. Also know that over-jetting can damage pipe and that downstream surcharging can occur.
Rule of thumb
Match the tool to the problem: grease = jetting; roots = root cutter; heavy solids = bucket/mechanical; structural defects = rehab (CIPP, slip line, burst).
Worked example
A line shows heavy root intrusion at joints. Jetting alone clears flow temporarily; schedule root cutting, then evaluate for CIPP if joints are deteriorated.