I have two research fields. The main field can be summarized in the question: What are the technical, environmental and economic consequences of making a change to the urban water system? The aim is to develop decision support for urban water system planners. My colleagues and I are using engineering skills and models to simulate and predict the operation of the water systems now and in the future. Then we use lifecycle assessment, eco-effciency and multicriteria analysis to assess the performance of the water systems. One example is our use of water quality modelling to and lifecycle assessment to determine the environmental impact of designed drinking water quality e.g. from desalination or softening. The second field is related to the safe operation of water supply distribution systems and the use of hydraulic models and GIS to assist the monitoring and documentation of safe water quality.