This document specifies the general principles for the management and control of cleaning operations in drain and sewer systems and specifies requirements for implementation of cleaning programmes and for working practices. It is applicable to drain and sewers systems outside buildings, which operate essentially under gravity, from the point where the sewage leaves a building or roof drainage system, or enters a road gully, to the point where it is discharged into a treatment works or receiving water. Drains and sewers below buildings are included provided that they do not form part of the drainage system of the building.