Groundwater is a valuable resource that must be protected, since in Switzerland ~80% of drinking water is obtained from groundwater (incl. spring water). Particularly powerful groundwater deposits are often located along large river courses, which often represent heavily populated areas of Switzerland. Contamination from various sources, anthropogenic influences on the hydrogeological system, and climate change have a major impact on groundwater quality and quantity. In order to grasp and better understand hydrogeological issues and challenges under the pressure of new developments and to work on missing basics, there is a great need for a continuous competence building, technical support and a smooth Switzerland-wide exchange between research and practice. To make a significant contribution to this, the CH-GNet network was created.