The present paper deals with the improvement of infrastructure asset management of urban drainage systems (UDS). A numerical tool for assessing the existing management procedures is proposed. It is based on a participatory methodology for the construction of a set of performance indicators. This methodology consists of two phases. The first one concerns the identification of priority objectives, criteria and indicators related to the management of the UDS infrastructure. The second phase concerns the assessment of the global performance for each identified objective. Performance measurement scales are first defined for all the elements of the proposed methodology. Then, the Fuzzy Analytical Hierarchy Process (FAHP) is used for the weighting stage, and the Weighted Sum Method is used for the aggregation of indicators and criteria. To illustrate this methodology, a case study concerning Bejaia City in northern Algeria was carried out. Two priority objectives are identified for this case, they are divided into 6 criteria and 31 indicators. The results of the application of the developed tool highlighted some weaknesses that need improvements in the actual management procedure applied by the local sanitation services.