Plumbing service
Trenchless sewer repair
Short answer
Trenchless sewer repair fixes or replaces a sewer line through small access points instead of a full-length trench. Relining (cured-in-place pipe) forms a new pipe inside the old one; pipe bursting pulls a new pipe through while breaking the old one apart. Neither can correct a sagging line, and the pipe has to be cleaned and inspected first.
Updated · Editorial team; not yet technically reviewed
Trenchless Sewer Repair at a glance
- Two main methods
- Relining (CIPP) and pipe bursting.
- Good candidates
- Cracked, root-damaged or leaking lines that still hold their shape (relining), or badly damaged lines on a reasonable grade (bursting).
- Poor candidates
- Sags, fully collapsed sections (for relining), and very tight bends.
- Required first
- Cleaning (often hydro jetting) and a camera inspection.
How relining (CIPP) works
Clean
Roots, scale and debris are removed so the liner bonds and cures against the old pipe wall.
Measure and wet out
A felt or fiberglass liner is cut to length and saturated with resin.
Insert
The liner is pulled in or inverted into the pipe with air or water pressure, then held against the wall by a bladder.
Cure
The resin hardens with hot water, steam, UV light or at ambient temperature, depending on the system.
Reopen connections and verify
Branch connections covered by the liner are reopened with a cutter, and a final camera pass confirms the result.
How pipe bursting works
A cone-shaped bursting head is pulled through the old pipe by a cable or rods from a pit at the other end. It fractures the old pipe outward into the soil while pulling a new, seamless pipe (usually high-density polyethylene) into its place. The new pipe can be the same size or larger than the old one.
Relining vs. bursting vs. digging
| Situation | Relining | Bursting | Open trench |
|---|---|---|---|
| Cracks and root entry, pipe keeps its shape | Good fit | Possible | Possible, more disruptive |
| Pipe collapsing along its length | Poor fit | Good fit | Good fit |
| Sag / belly | Can't fix | Usually can't fix | Fixes it |
| Under a driveway, slab or mature trees | Good fit | Good fit | Most disruption |
| Needs a larger pipe | No (slightly smaller) | Yes | Yes |
Questions to ask a trenchless contractor
- Which method and liner or pipe system, and what's the expected service life according to the manufacturer?
- How will branch connections be reopened, and will I get a final camera video?
- Does the quote include cleaning, the pre- and post-inspection, permits, and pit restoration?
- What does the warranty cover, and who backs it?
Common questions
Is trenchless sewer repair cheaper than digging?
Not always per foot, but it often costs less overall when digging would mean removing and restoring a driveway, patio, landscaping or mature trees.
Does relining make the pipe smaller?
Slightly, by the liner's thickness. The smooth interior usually offsets this for flow in residential lines.
Can trenchless repair fix a sagging sewer line?
No. Both relining and bursting largely follow the existing path. A belly normally needs excavation to reset the slope.