Water supply systems (WSSs) process optimization can be considered as one of the  highest importance priorities in core public infrastructures management challenges. The  primary goal of water service is to operate this valuable asset with the utmost efficiency  possible at an acceptable cost throughout its life. Achieving this objective primarily  requires assessing the existing performance of all components of the WSS using distinct  performance indicators (PIs). Various international water bodies have developed  detailed performance assessment frameworks based on multiple indicators to  comprehensively cover all WSSs. On this basis, the present study proposes a conceptual  WSSs performance evaluation framework linking various water collection, treatment,  and distribution processes with their PIs groups and corresponding categories. However,  multi-attribute utility theory (MAUT) was used to provide a stepwise approach, starting  abroad range of quantitative and qualitative drinking water performance evaluation  process depending on specific operating conditions. Meanwhile, the integrated  performance evaluation indicators (IPEI) for elven extended Cairo drinking WSSs were  developed to determine the overall complex interrelationship between the targets  evaluating indicators sets. The results of this study are a very useful entry point for water  services providers to put forward their basis selection, ranking of WSSs critical  elements, and consequently developing the required future plans