Resumen: This report provides a comprehensive definition of sustainability aimed to provide a reference framework within the TRUST project. Sustainability for the Urban Water Cycle Services (UWCS) is defined in 5 dimensions (including the classial tripple bottom line plus two additional enabling dimensions) and includes the detail of objectives and assessment criteria that should be used to define assessment systems within TRUST. In other words, the TRUST sustainability framework defined in this report should be used as a reference when developing any performance assessment system within TRUST, as it provides the basic objectives and assessment criteria that should lead to adequate performance metrics. A practical implementation of this approach is the development of the online self-assessment tool which constitutes TRUST Deliverable D312. The self-assessment tool makes use of the framework developed for the whole project and develops it into a set of performance metrics to perform a quick and initial assessment of the sustainability of the system. The second part of this report provides the details on how the self-assessment tool operates, the metrics used and how the assessment is provided. As a matter of fact, D311 should be seen as the document providing the technical insight on the self-assessment tool presented in D312.
