The European Space Agency, in the context of the "Earth Observations Science for Society" Programme, and CNES are organising a sequel joint event to Hydrospace2021 and EO4Water2020, called 5th Space for Hydrology Workshop. This time around the Hydrospace Workshop is organised in collaboration with GEWEX (and other sponsors to be confirmed), seeking opportunities to explore joint solutions with a broader view on key science questions for Research and Development, up to Operational use of remote sensing information. The aim of getting together during 5 days in a brainstorming workshop-style is to strengthen the collaboration between the four critical water communities: in situ, modelling and space observation scientists as well as “non-scientific” users such as water managers to address the needs of the application community.