This article aims to determine an efficient way to create a low-tech rain-powered triboelectric generator. The harvester can be useful to power some low power devices (sensors, lights, IoT...) or to compensate for other energy sources in building for example. For this purpose, a fluid flow triboelectricity is studied. So, a setup that aims to measure the energy possibly gathered was built, and optimized as much as possible with recycled materials. A great work was made on pipe optimization concerning dimensions, electrodes position, resonances and embedding. The setup was also improved to spend the least water since it is the limiting factor. For the flow rate influence was studied and the results were summarized on an efficiency graph. Then, the impact of triboelectricity and the ways to make it more efficient were reviewed by considering material optimization, surface charge managing, placement. Thus, the magnitude of recoverable energy was evaluated to determine the best way to build the generator. Finally, the generator was built to prove its feasibility and offer an electric voltage in open circuit of 100mV to 600mV.