Crawler Cameras for Mainline Sewer Inspection
A crawler camera is a motorised, remote-controlled tractor that carries a pan-and-tilt camera through mainline sewers, typically 150mm diameter and up. Unlike a push camera, it travels long distances under its own power, climbs through silt and debris, and surveys pipes far beyond the reach of a push-rod. It is the right tool for adoptable sewers, large-diameter mains and long runs.
When a push camera runs out of reach or the pipe is too big, you move up to a crawler. Here is when you need one and how to get the most from it.
When do you need a crawler instead of a push camera?
- Diameter: mainlines from about 150mm up to large-diameter sewers a push camera cannot fill or light.
- Distance: long runs of hundreds of metres, where a push-rod simply cannot travel.
- Adoption and mainline condition surveys for water authorities, which expect crawler-grade footage and coding.
- Pan-and-tilt detail: the ability to turn and look into laterals and at specific defects.
What makes a crawler survey work?
- Wheel and tyre choice matched to pipe size and condition, so the tractor keeps traction through silt.
- Elevated, pan-and-tilt camera that can be raised in larger pipes and rotated to inspect joints and connections.
- Strong, even lighting, because large pipes swallow light and detail is lost without it.
- Accurate meterage and a sonde, so defects can be coded and located for repair.
How do you locate a defect found by a crawler?
Exactly as with a push camera: when the crawler reaches a defect, you stop, switch your locator to the camera's sonde frequency, and pinpoint position and depth from the surface. On a deep mainline this is essential; you are not digging an exploratory trench across a road on a guess. The method is in precision drain repair with sonde locating.
Coding mainline surveys
Mainline and adoption surveys live or die on the coding. Footage must be classified to the WRc standard so the water authority can act on it, and on long runs that is where AI-assisted coding earns its place by speeding up the review. See our WRc and AI coding guide.
Buy or hire?
Crawler systems are a significant investment and best justified by steady mainline or adoption work. For occasional large-diameter jobs, hiring is the sensible route. Talk to us about CCTV drain survey equipment hire, and see the full survey method in the professional drain CCTV handbook.