It also aims at the advance in visual inspection methods, with higher accuracy, and development of a planning approach to the identification, assessment, and risk-based classification of anomalies. The general methodology also includes planning of inspections and setting rehabilitation priorities. This approach to decision support facilitates the identification and resolution of the most serious anomalies and the establishment of continuous action by CML staff to detect and rehabilitation of high-risk situations. The main priority is the identification and diagnosis of critical sewers, in terms of the structural condition, of the large sewers in the city of Lisbon.