WatERP will develop a web-based “Open Management Platform” (OMP) supported by real-time knowledge on water supply and demand, enabling the entire water distribution system to be viewed in an integrated and customized way. The OMP will provide to the user inferred information regarding water supplies, flows, water consumption patterns, water losses, distribution efficiency, and water supply and demand forecasts, within a web-based unified framework. This information will be stored in a Water Data Warehouse making use of semantics and common language and open standards (such as WaterML 2.0) which will be defined in the ontology developed to ensure interoperability and maximize usability. In addition, external linkages to costs, energy factors, control systems, data acquisition systems, external models, forecasting systems and new data sources will be made possible for easy integration into the system. The main purpose of this information interaction and processing will be to improve the matching between supply and demand. To achieve this final goal, a Decision Support System (DSS) tool will support coordination of actions throughout the entire water supply distribution chain, prioritization of water uses, distribution efficiency improvements, and water, energy and cost savings. A Demand Management System (DMS) will analyse socioeconomical drivers and policies to improve demand management. The project outcomes will be tested and validated in two pilots representative of different European water problems (water scarcity - water abundance) with clearly distinct objectives (optimize water resources management - improve water energy efficiency).