The design of water supply infrastructure depends on local conditions such as geophysical features, available technology, traditions, culture, and available human and economic resources. The costs for designing, building, maintaining, monitoring, and replacing the required infrastructure escalate when any of these factors is inadequate or insufficient. Furthermore, effects of global climate change increase the risk associated to existing infrastructure, calling for more robust, flexible, and adaptable technologies. We present the design and development of the first physical prototype of the Filardo Pump™, a low-cost, robust, sustainable, water-powered pump that addresses these challenges with many advantages over existing technologies: 1) it requires no external energy source, 2) it works immersed in a free-flowing, unaltered body of water, 3) it is operable in shallow water and low flow conditions, 4) it has low cost and low weight relative to work performed, and 5) it can be made small for households or scaled up for industrial applications. We show proof of concept for this novel pump and describe its development through scaling geometrical aspects and testing different materials for its operation. The proposed technology presents an opportunity for low-cost, sustainable, low carbon footprint water supplies for households, agricultural and industrial applications everywhere, not just in the rural developing world. •Development of a self-sustained water pump with applications to energy harvesting.•Constructed with two plastic sheets, with a permanent but unstable deformation.•Materials/construction ensure a robust, sustainable, economically affordable device.•We show proof of concept and develop its performance by scaling geometrical aspects.