Extracting power from the excess pressure of urban water pipelines by in-pipe drag-based turbines is a newly developed method for clean energy production on a small scale. The performance improvement of these turbines as a sustainable and clean energy production device is subjected in this research by studying the effect of turbine blade geometry. In this regard, the focus of this research is on studying the performance of three common blade profiles for free flow drag-based turbines, including the S-Shaped, Semi-Elliptic, and Bach profiles. Firstly, using an existing test ring, the fabricated turbines with different blade profiles are experimentally tested. Numerical study is also performed and simulation accuracy is validated with the experimental results. After that a theoretical method is introduced for evaluation of the produced torque by turbines with different blade profiles. The outcome of these three methods unanimously proved that in case of in-pipe turbines, the turbine with Bach profile blades has better performance than the others. Also, the developed theoretical approach proved to be a fast and reliable method for performance evaluation of in-pipe turbines. Further analysis, which is performed by numerical simulations is used to show the flow field behavior around turbine in more detail. This is to distinguish the reasons for existing difference among the performance of the studied turbines.