In view of increasing ecological damage, increasing competition in many areas, and rising social conflicts the necessity of comprehensive notes of solution grows in order to reach economic, ecological and social goals simultaneously. Recently, public water supply and wastewater disposal are also affected by these problems. Here, the focus must be laid on the long-term protection of the essential resource drinking water. In politics and science, the discussion of the model 'Sustainable Development' as a suitable solution has increased. The model is widely recognised but its concrete contents are still not fully discussed. Besides, a conversion of the model can only be conducted on site by the huge number of decision makers. For this reason we performed an empirical analysis in order to get to know their understanding of 'Sustainable Development' and the resulting needs for information and techniques of assistance for the decision making process in practice.