As-built surveys are undertaken to establish the actual position on the ground of features versus the proposed design location. Typically, as-built surveys are carried out on completed developments such as a housing estate so that the responsibility of maintaining the development can be passed on to the local authority.

All roads, boundaries, buildings and services are surveyed together with the foul and surface water manholes. The local authority may also require the cover level, invert level, pipe details, direction of flow and grade calculations for all surveyed manholes.

As-built surveys can also be carried out one or more times during the construction phase to ensure all aspects of the project are been constructed correctly and to highlight any problem areas.