Knowing a pipe is broken is only half the job — repairing it economically depends on knowing exactly where, and how deep.
The standard method is camera plus sonde:
- The CCTV camera travels through the drain until it reaches the fault — the crack, root mass or collapse is visible on screen.
- The camera head contains a sonde, a small transmitter emitting a signal at a known frequency.
- Above ground, the operator sweeps a locator receiver until it pinpoints the signal, marking the spot directly above the camera head — and reading its depth.
The result is a paint mark on the lawn or driveway saying, in effect, "the damage is directly below here, at this depth." For an excavation repair, that is the difference between one accurate hole and a trench dug on guesswork. For a reline, it confirms measurements and access points.
Related tracing tools:
- Line tracing — the same locator can follow the whole camera path, mapping where drains actually run across the property (often nothing like the diagram).
- Dye testing — coloured dye flushed into a fixture reveals which pipe it really connects to, exposing cross-connections.
- Smoke testing — smoke introduced into the drain escapes at faults and unsealed openings, tracing smells and leaks that cameras cannot see.
Combined, these tools mean underground drainage can be diagnosed with precision comparable to anything above ground — no exploratory digging, no educated guesses, and repair quotes based on facts.