Water (and its deteriorating quality) may be the most severe stress on the exponentially growing human population in the next century. Problems are becoming increasingly complex and diverse and require more and more specific knowledge, and efficient integration across various disciplines, sectors, countries, and societies. The major challenge addressed is whether we are prepared to realize the desired integration and to resolve the large amount of existing gaps and barriers. The paper analyzes major past and desired future trends in water quality management. A number of issues are selected such as the identification, occurrence, and perception of various problems (e.g. eutrophication, acidification, global warming), pollution control types, wastewater treatment, modeling and monitoring, planning and environmental impact assessment, legislation and institutions, the notion of sustainable development, and the role of science and engineering. The past two decades showed tremendous developments in water quality management. In spite of these, the focus of the present discussion lies mostly on pitfalls to disseminate lessons and questions which are crucial to likely future problems and desired improvements.