Located on the Seine river front, close to a key metropolitan route (the Francilienne), Évry water depuration plant is a major infrastructural element that is at once symbolic and highly functional, reflecting environmental, technical and urban considerations. The first plant was built in the 70s and the aim of this renovation is to increase and optimize its capacity. The urban dimension of the equipment has guided us towards a strategy of opening-up and hospitality. Previously rejected and hidden, this infrastructure is now relocated on the urban scene, so as to have a public role and to become symbolic. Regularly open to visitors, this equipment will become both a landmark and an experiential water filtering park. The formal strategy consists of a main axis along the river where gardens, new buildings and tanks are located. Buildings will be renovated and their façades completely redesigned as urban scale filters.