This study presents the results of tests conducted in 2009 and 2010 on experimental sites installed on the roof of the Science and Education Building of the Wroclaw University of Environmental and Life Sciences. The aim of the analysis was to determine the retention capacity of green roofs and the runoff delays and peak runoff reduction during rainfall recorded in Wroclaw conditions.

The research shows that green roofs allow to reduce the volume of runoff stormwater in comparison to conventional roofs, that they delay the runoff in time and influence the reduction of the maximum runoff intensity, and thus may limit the impact of stormwater on the stormwater drainage and combined sewage systems.

At present, stormwater management is one of the key issues in urban policy. This is due to the increasing urbanisation, climate change, the growing threat of extreme (weather) events and the need to protect water resources. Legislation plays an essential role in the process of project planning and implementation. The recognition of opportunities and barriers contained in these regulations forms the basis for action by the central government, local authorities and investors. The article aims to analyse legal provisions, administrative decisions and factual circumstances that provide the foundation of administrative court rulings in Poland and regard the legal possibilities of rainwater management in urban areas. The adopted research method allows for/includes the author’s interpretation and formulation of de lege ferenda conclusions. The results of analyses of both European and national legislation and case law indicate that there is a problem with the interpretation of existing legislation and the lack of legal definitions of basic equipment and solutions in the field of water law, for instance. Such legal circumstances make it difficult to make the required legal decisions, and have a negative impact on the timing of implementation and number of these muchneeded projects.