At the Campus of TH Lübeck special infiltration areas are used for the infiltration of rainfall collected on rooftops. These infiltration areas prevent the water from going into the sewer systems and compensate for the loss of direct infiltration on sealed surfaces. They are meant to improve the water balance and keep it closer to the natural state before urbanization. However, these infiltration areas may create a fast and very efficient percolation and even bypass the soil storage resulting in an increase in groundwater recharge and increases of groundwater levels. Therefore, a hydrological analysis should be done to assess the functionning of these infiltration ponds.