The new inland positions of Enteromorpha compressa (L.) Ness [Ulva compressa L.] are located in Poznań streams: Michałówka, Dworski and Świątnica. Taking into account the morphology the freshwater form of E. compressa is very different from its see forms. Mature thallus reach impressive size from 180 cm in length to 8 cm width. All positions of that see-like macroalga are located near the A2 route (Nowy Tomyśl - Stryków). Sewage coming from the route fall into streams, in which great mass growth was observed. It is assumed, that this sewage probably has an impact on intense thallus growth.