This paper proposes a methodology for managing complex sewerage networks based on the concomitant use of two performance evaluation methods namely (1): the Failure Modes, Effects and Criticality Analysis (FMECA) and (2) the Analytical Hierarchy Process (AHP). The FMECA is used to determine the risks of structural failures making it possible to establish a methodology for managing these failures. The AHP is used to check the relationship consistency between the performance indicators allowing the determination of the overall performance (OP). This proposed methodology was also utilized for the urban sewerage network of Oued-Kniss in the city of Algiers, Algeria, as part of the efforts engaged for sustainable and efficient management.