This paper analyses the effects of new buildings in difficult soil and water conditions (high groundwater level, flood terrace), within large cities. These effects were analysed in two ways, both in relation to the durability of the building structures and by assessing their impact on the surrounding environment, with particular reference to the pollution of watercourses located within the estate. The problem was discussed using the example of a housing estate, known as Wilanów town, located in Warsaw near a surface watercourse, i.e. the Służewiec Stream, with a network of tributary/drainage ditches/channels. For this purpose, an assessment of the technical condition of the building sited in difficult soil and water conditions after several years of operation was used, as well as the results of studies of pollution levels in the adjacent, watercourse. With regard to the building object, the influence of groundwater on the tightness of the insulation of the below-ground parts of the building was analysed. The analysis of changes in contaminant levels in the watercourse was carried out with reference to the heavy metal content of the bottom sediments.