Blue-green infrastructure is a network of natural and near-natural areas that has a positive effect on the quality of urban environment.This multifunctional planning approach addresses different issues and objectives depending on whether the focus is on the blue (water) or the green (vegetation) elements.Green-motivated projects aim to densify urban vegetation and include the growing sector of building greening.A good climatic effect of vegetation can be achieved by sufficient irrigation.In many cases,this approach results in additional water requirements.Blue-motivated projects consider water accumulation in cities (e.g.,by heavy rainfall) as a waste product and look for solutions for local drainage and evaporation.These planning approaches offer only one-sided solutions and create no sufficient interfaces between water availability and water demand.Based on four case studies,this work examines the extent to which blue-green projects take advantage of the possibilities for the synergetic use of resources.The projects are analyzed graphically by applying the daily tools of architects as a scientific method.A graphic presentation of the blue and green components makes existing solutions and missing links visible.Analytical results show that buildings can be considered to be an interface for blue-green systems.Mloreover,the possible synergies are often overlooked during the planning process.This fact highlights the need for a new planning approach that interlinks blue and green aspects that are already in the early planning stages.