A belly (also called a sag or dip) forms when the material under a pipe compacts or washes away, letting a section drop below the design line. Unlike a full collapse, the pipe is often still intact — it just holds a puddle.
Small bellies may only need monitoring; deep bellies that trap solids usually lead to recurring blockages and eventually need the section relaid or, in some cases, relined.
A defect term describing localised settlement in a pipe run.
Commonly under driveways, in filled ground, and where trenches were poorly compacted.
A CCTV drain inspection is the standard way to confirm whether this is what's happening in your pipes: the camera shows the condition on screen, a locator pinpoints the exact position and depth, and you get a recorded report before any repair decisions are made.
A CCTV drain inspection shows exactly what's happening inside your pipes — no guesswork.