The ideal corporate organisation to fulfil the Ruhrverband's main responsibilities in an economic way is that of a corporation under public law. However, tasks and business areas kept coming along which could not be very well catered to within the original structure. One example is the development of tourism around the reservoirs, which could only be promoted in partnership with the neighbouring cities and districts as the development of tourism is in their very own interest. Another examples are the economic exploitation of the reservoirs' hydropower potential, carried out by Lister- und Lennekraftwerke GmbH, and the economic disposal of sewage sludge, carried out by WFA Elverlingsen GmbHin cooperation with a power plant operator. In order to be able to participate in cooperations under private law, RWG Ruhr-Wasserwirtschafts-Gesellschaft mbH was founded as a wholly-owned subsidiary of the Ruhrverband. It offers the Ruhrverband's members theoretical and practical support in the operation of their local drainage.