Trenchless

Trenchless Sewer Repair Explained: Pipe Lining vs Pipe Bursting

By San Diego Sewer Repair · September 10, 2026 · 5 min read

"Trenchless" is two different jobs that get sold under one word. One puts a new pipe inside your old one. The other destroys your old pipe and pulls a new one through the hole. They cost about the same, they both keep the driveway intact, and they're not interchangeable. Which one fits depends on what's wrong with the pipe, and in San Diego, on whether the pipe is the cast iron under the house or the clay out in the yard.

Cured-in-place pipe lining (CIPP)

A flexible tube of felt or fiberglass is saturated with a two-part epoxy resin, then pulled or inverted into the existing pipe from an access point, usually the cleanout or a pulled toilet. It's inflated with air or water so it presses against the old pipe wall, and cured with hot water, steam or a UV light train over three to six hours. When it's done you have a smooth, jointless pipe about a quarter inch thick sitting inside the old one. The old pipe just holds the shape.

Where a lateral has branch connections (a second bathroom tying in, a kitchen line), those get covered by the liner and then reopened with a robotic cutter guided by camera.

What lining needs: a host pipe that's still roughly round and continuous. It will bridge cracks, small holes, offset joints up to about a quarter of the pipe diameter, and root-damaged joints once the roots are cut out. It will follow gentle bends. It reduces the inside diameter slightly, which on a 4-inch line that's been scaled to 3 inches for a decade is an improvement, not a loss.

Pipe bursting

A conical steel bursting head is pulled through the old pipe by a cable or a hydraulic rod system anchored in a pit at the far end. The head is bigger than the pipe. It splits the old clay or cast iron and pushes the fragments out into the surrounding soil, and a new high-density polyethylene pipe, fused into one continuous length, is pulled in directly behind it. The result is an entirely new pipe on the old alignment, the same size or one size larger.

What bursting needs: two pits, one at each end of the run (often the house end and the curb or the main), a reasonably straight run, and soil the fragments can be displaced into. It handles pipe that's too damaged to line: large offsets, partial collapses, Orangeburg that's gone egg-shaped. It can upsize a 4-inch line to 6-inch. It's the wrong tool under a slab or inside a building, and it doesn't like tight bends or a lot of branch connections.

Side by side

What that means on a San Diego house

Cast iron under the slab. Lining, almost always. There's no way to burst under a house without cutting the floor, and the whole point is not cutting the floor. The line is descaled by jetting first, cameraed to confirm the wall is still there, and lined from a fixture or cleanout. See under-slab sewer repair.

Clay lateral with roots at the joints. Either. Lining if the joints are only slightly offset and there's an easy access point. Bursting if a joint has shifted far enough that a liner would have to bridge a real gap, or if you want the line upsized.

Cast iron lateral with channel rot. Lining if the top half of the pipe is still holding shape. Bursting if the camera shows sections where the pipe is barely a pipe.

Anything with a belly. Neither, at that spot. Both methods follow the old path, so a sag in the old pipe becomes a sag in the new one. The belly gets dug and re-bedded, and the rest of the line can be lined or burst on either side of it. A contractor who lines over a belly has sold you a permanent low spot.

The last 15 feet to the main. Both work. This is the stretch under the sidewalk and street that, in the City of San Diego, belongs to the owner, and it's the stretch where trenchless earns its keep by not opening the road. The connection at the main still gets inspected under a right-of-way permit either way.

The trade-offs nobody mentions

Lining is only as good as the cleaning before it and the cure. Resin that's cured too fast wrinkles; a liner pulled through uncut roots fails at that joint. Ask to see the post-cure camera footage. Bursting displaces soil, and on a lateral that runs within a foot or two of a water service, a gas line or a shallow foundation footing, that displacement has to be thought about. DigAlert marking is required before either job, and it's a bigger deal for bursting.

Cost is close: lining about $90–$200 per foot, bursting $100–$250. The pits are what separate them on a short run. The trenchless page has the pricing, and trenchless cost in San Diego covers what makes two bids differ.

Who decides

The camera. Anyone who tells you which method you need before they've run one is quoting from the driveway. Get the inspection, watch the screen, and the choice is usually obvious by the time the camera reaches the street.