Vaasa, located on the Gulf of Bothnia, is representative of medium-sized cities on the coast of the Baltic Sea. This article discusses Vaasa's impact on the surrounding sea area and the city's reactions to the pollution of the sea. The history of wastewater treatment in Vaasa strongly suggests that first-generation environmental problems, e.g. the pollution problems caused by municipal wastewater discharges, were solved only as a last resort after a prolonged development process. The first wastewater treatment plant was completed in 1953. In the long run, municipal policies became more costly for the environment and for the town itself than would have been the case if the option of constructing a central treatment plant had been accepted in the first instance. In Vaasa, the environment itself did not provide the incentive, the change was motivated by health risks, noxious odors and poor outdoor-bathing possibilities that resulted from municipal wastewater discharges. No action was taken until ultimately forced by necessity. This article also discusses social science approaches to environmental studies.