A rehabilitation scheme at the more than 100 year-old Fully hydro scheme, where the penstock had shown signs of ageing, has involved converting the original single power station into a cascade of three plants, which have been integrated in a municipal water supply system. This paper presents the main stages of the rehabilitation studies, the reasons for the solution adopted, as well as an overview of the construction challenges. The scheme is now nearing completion, with the last small plant scheduled to be commissioned in December.