Waste water taxes have been introduced or planned In several Swiss cantons (states). In numerous communities, charges for water and waste water have been altered and/or increased to correspond better to the polluter-pays principle. This project is to assess the impact of the modifications in taxation the behaviour of households, industry, institutions as well as on the environment. Furthermore, the political process and the acceptability shall be discussed based on successful and not successful tax projects. Statistical data analysis and interviews will be the main techniques in the framework of an analysis using economic and political sciences.The objective of the research proposed is to test the following (draft) hypothesis for cantonal taxes on waste water and water as well as for polluter-pays oriented modifications in water and waste-water charges of communities:o Hypothesis 1: These taxes and charges have a considerable impact on the behaviour of the polluters (or resource consumers, respectively), individuals, firms as well as public institutions. This makes the implementation of control and command measures much easier or even unnecessary.o Hypothesis 2: During the political process, these taxes lose their incentive effects which was originally intended. Finally, their only effect is to finance the tasks in the waste water and water sector without really influencing on the behaviour of the polluters.o Hypothesis 3: Such taxes and charges are more successful if they are introduced in parallel with a communication and some regulative activities and if the actors concerned (industry, waste water plant managers etc.) are involved timely and to a large degree.To complementary methodological approaches are proposed:o In a top-down approach, data on water, waste water and pollutant flows will be statistically analysed to test for influences of alterations in the taxes and charges (econometric/regression analysis). The main questions are: What is the influences of taxes and charges? What other factors play an important role (e.g. economic prosperity, technological changes, alterations in regulations?o In a bottom-up approach, qualitative interviews of actors involved as well as of experts may be complemented by a written questionnaire. The answer shall help to validate and interpret the top-down results. They are also a key to understand the barriers of the implementation of polluter-pay oriented taxes as well as the barriers to adaptations in the behaviour of the actors after the introduction of taxes. Questions to be asked may include issues like: What barriers have you felt while planning altered tax systems? What were the key elements to success? What informal and psychological factors have been important for the political process and for the changes in the behaviour of the polluters? What effects have been noticed after the announcement of the tax plans but before their actual introduction (announcement effect)?Furthermore, the co-operation with other projects will support especially the analysis of political and psychological factors. In a qualitative synthetic assessment, general conclusions on the three hypothesis are drawn. The applicability of the findings for other environmental sectors and other instruments will be discussed.