In recent years, pumps used in turbine mode (pump as turbine, PAT) have started to appear as a viable option to reduce pressure in water distribution networks in addition to energy production at micro scale. In this study, evaluation of performance of a recently installed PAT system in Antalya City, Turkey, is presented for the first operational period of approximately 5 months. This full-scale PAT system was implemented in a parallel pipeline with a pressure reducing valve. The operation of the installed PAT system was continuously monitored online for flow rate, power and pressure. The installed PAT system, being in operation since 26 January 2016, works efficiently in a wide range of inflows (130–300 m3/h) and the produced energy varies between 0.7 and 8.4 kWh for a reduction of approximately one bar pressure head with an average efficiency of 60%. Based on the initial 5 months of operational data, environmental benefits of green energy production, reduction in physical water losses and carbon dioxide emissions were evaluated. Based on the implementation cost of the PAT system and the revenues from the environmental benefits, payback period of this specific full-scale PAT application was computed as 53 days or 1.8 months.