How trenchless sewer repair works

First, the camera

Nothing sensible happens before a camera inspection. It shows the pipe material, every defect with its footage mark and depth, and whether the pipe still holds its shape and slope. That last point is the whole decision: a pipe with its shape can be lined; a pipe without it has to be replaced.

Method one: cured-in-place pipe lining

The line is cleaned with a hydro jetter. A felt or fiberglass tube saturated with resin is pulled or inverted into the pipe from the cleanout, inflated against the wall, and cured with hot water, steam or UV light. When it hardens there is a new, jointless pipe inside the old one. Branch connections are reopened from inside with a robotic cutter. The line is filmed again. One day, no trench. More on lining →

Method two: pipe bursting

A pit is dug at each end of the run. A cable is pulled through the old pipe, a bursting head with new HDPE pipe fused behind it is attached, and a hydraulic unit pulls it through. The head splits the old pipe outward into the soil and the new pipe takes its place at the same depth and alignment. The ends are connected, the city inspects if the street connection was involved, and the pits are backfilled. One day, two small holes. More on bursting →

The smaller tools

A sectional point repair lines a short section over a single defect. Spray-applied lining rebuilds under-slab cast iron with too many bends for a felt liner. Hydro jetting is both the preparation for lining and, on a sound line, a maintenance service in its own right.

How the choice gets made

• Cracks, root intrusion, small offsets, channeled cast iron — pipe still round and holding grade: line it.
• One crushed joint on a sound line: point repair.
• Collapsed run, belly holding water, undersized lateral: burst it.
• Cast iron under a slab with several tight bends: spray-applied liner.
• A long run that has lost grade entirely, or a lateral that needs a new route: spot excavation or a bore, and a contractor who says so.