Sewer mains run under streets, easements and sometimes private land, collecting flow from each property's house drain at a connection point. In Brisbane, mains are the responsibility of the water utility; everything on the property side of the connection is the owner's.
That boundary matters during blockages: a main surcharging affects multiple properties and is the utility's job, while a blockage upstream of the connection point is a private repair.
Transports wastewater from many properties to treatment facilities.
Under roads, footpaths and easements, at depths from one to many metres.
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.