The hydrological scientific and operational communities are faced with new challenges. There is a demand for detailed water information for large regions and new environmental issues to deal with, which request advanced technical infrastructure merged with up-dated hydrological knowledge. Traditionally, the hydrological community is disaggregated. In this paper we suggest a collaborative approach and invite both researchers and operational agencies to participate in the development of a common European core service providing free access to water information. We present the idea of starting from the new E-HYPE model and its advanced technological infrastructure and open source cod, using a bottom-up approach.