The ROSES observatory stands for Observatory network of groundwater systems at France level. It gathers more than 77 000 water points, with 74 000 groundwater quality points and 4400 monitoring wells, distributed among 275 monitoring networks (early warning networks for industrial installations, national and local groundwater monitoring networks, water uses networks with sanitary goal). All the variety of hydrogeological settings are concerned, alluvial, sedimentary basins, karst, volcanic and fissured hard rock aquifers, in Metropolitan territories as well as French overseas territories. 1450 monitoring wells are under the responsibility of the BRGM. All data are stored within the ADES database (http://www.ades.eaufrance.fr), a collective work gathering AFB, the Ministry of Environemental and Inclusive Transition, the Ministry in charge of Health, Water agencies and DREAL. Its IT development, national animation and hosting are entrusted to the BRGM. There are more than 13 300 000 groundwater level data as well as more than 60 900 000 groundwater analyses. ROSES observatory, a national monitoring network of quantitative and qualitative status of groundwater has been reinforced in the framework of the implementation of the European Water Directive. If ROSES observatory has been set up to answer water management issues, several scientific questions may be addressed such as (i) the impact of climatic change on aquifers behaviors at national scale considering assimilation of groundwater level data and modeling, (ii) the link between the geochemical signature of groundwater and the geological settings in the saturated zone at national scale, (iii) the transfer time and contaminants behavior of agriculture origin as well as emergent contaminants within aquifers of large catchments in France, and (iv) the development of database tools (interoperability ie) and data treatment (statistical tools).