Sewer record office

A sewer record office is the office or service that holds the records of public sewers within a local authority area. In Greater London the records are primarily managed by Thames Water, with each borough also holding limited historic drainage drawings from predecessor authorities. The office responds to formal records requests submitted by conveyancers, surveyors, drainage engineers and design teams, providing plan extracts and supporting information. The records form a starting point for assessing responsibility under the Water Industry Act 1991, planning new connections under Building Regulations Part H and identifying adopted assets under earlier section 104 agreements. In practice, records often need to be supplemented by a CCTV drain survey to BS EN 13508-2 and a drain mapping exercise by qualified engineers to confirm actual conditions on site.