Your Questions › Category: Plumbing Questions › What Is Trenchless Pipe Repair and How It Works? 0 Vote Up Vote Down Terry Ross Staff asked 3 years ago Print This PageWhat Is Trenchless Pipe Repair and How It Works? 1 Answers 0 Vote Up Vote Down Terry Ross Staff answered 3 years ago Print This PageTrenchless pipe repair is the use of PVC liners installed inside a pipe. Those liners fill all the gaps in existing rotten or rusted pipe, especially in old, degraded cast iron piping.