Drain mapping survey

A drain mapping survey identifies and records the location, direction, depth and connections of the drainage network across a property or site. Engineers combine CCTV inspection with sondes and electronic locators to trace the line of each run at ground surface, then produce a digital plan annotated with chamber positions, pipe diameters, materials and flow directions. The survey is often commissioned ahead of extension work, basement conversions or pre-acquisition due diligence on commercial sites across London. It also helps confirm whether a connection runs to a public sewer maintained by Thames Water or a private drain remaining with the freeholder. Outputs typically follow BS 1192 and CAD conventions and may feed into Building Regulations Part H submissions. The work is carried out by qualified engineers and produced as a clear scaled drawing.