The main cost factor in the construction and operation of drainage systems in residential areas continue to be the sewer systems for waste water and storm water. Surveys have shown sewer systems to be in an alarming state of dilapidation which , among other factors, may give rise to diffused ground water pollution over large areas. In order to make efficient use of the funds to be spent, progress must be achieved in the development of construction techniques, building materials, measurement, control, and processing technologies, as well as maintenance of the sewer system, while aspects of accident protection and prevention and improved working condition must be taken into account. In order for these efforts to succeed, problems of sewer hydraulics, pipe materials, sewer stress analysis and sewer construction methods must be clarified. Within the frame work of a main funding activity of BMFT, the development and demonstration of powerful techniques and methods of damage assessment, prevention and repair is to be funded with these objectives in mind. In particular, existing concepts and pilot projects are to be examined and the state of the art is to be advanced. Priority will be given to joint projects involving local governments, industries, and research institutions in these areas: Detection and quantification of contamination rising from leaky sewers. Methods of assessing the urgency of defects. Methods of removing contamination and repairing existing leaks. Majors of ensuring long-term leak tightness of the waste water transport system.