Repair or replace?

The decision sequence

In order: establish the symptom, restore flow if needed, inspect the full accessible run with distances recorded, map where the defects are and how severe each one is, confirm whether grade is intact, establish where the responsibility boundary sits relative to the defect, and only then evaluate methods against those findings.

Every step skipped moves the decision further from evidence and closer to whichever method the person in front of you sells. That is the entire failure mode this page exists to name.

Localized versus distributed failure

A localized failure is a defect with edges: it starts here, ends there, and the pipe on either side is doing its job. A distributed failure has no edges — the same problem appears repeatedly along the run because the material or the installation is failing generally.

Repairing a distributed failure may defer broader work without addressing the pattern. Replacing a localized failure spends money on pipe that was fine. The cost of getting this wrong runs in both directions, which is why the survey matters more than the sales pitch.

Line and grade set hard limits

Rehabilitation methods that work inside the existing pipe preserve its line and grade. That is a real constraint, not a caveat. If the footage shows water standing over a stretch of the run, lining that stretch produces a lined pipe with the same low spot. Correcting fall usually requires excavation and re-laying the affected section to a corrected grade; not every replacement method changes alignment.

The false binary

“Repair or replace” is a convenient headline and an incomplete menu. In practice the options include a targeted excavated repair, a sectional liner across a defined defect, full-length lining, pipe bursting, partial replacement of the failed portion, and full replacement. Several of these may be viable for the same line, and which ones qualify depends on the evidence rather than on preference — the trenchless guide sets out what each requires.

The evidence threshold

Before a decision of this size, you should be able to answer: how much of the run was surveyed, what was found and at what distances, what the pipe material is, whether grade is intact, what stopped the camera if anything, and what rules out the alternative approach. If two or more of those are unanswered, the decision is not ready — the next step is inspection, not a signature.