A translation of "Guide de conception et de gestion des reseaux d'assainissement unitaires", Paris 1996. This text looks at the design and management of combined sewerage networks, covering topics such as: data on rainstorm run-off pollution; different types of weirs and accessories; computation and measurement of characteristics of weirs; evaluation and improvement of hydraulic output and its treatment; location, checking and choice of weir and its improvement; regulations concerning weir wastes; and strategies proposed for action and improvement of knowledge.