The public drinking water supply in the western part of the Steinburg district, in the southern part of Rendsburg-Eckernförde and in Brunsbüttel is the responsibility of the Association, which operates three waterworks in Wacken, Kuden and Warringholz. Consequently, the Association is one of the largest water suppliers in Schleswig-Holstein. Supplying such a large area is only possible in the long run by means of a specific and sustainable management of the groundwater reserves in the region. The groundwater used for the supply is treated in the waterworks using large-scale filtration systems in order to obtain drinking water.