Population growth, climate uncertainties, and unsustainable groundwater pumping challenge aquifer sustainability worldwide. Existing methods to measure and monitor groundwater levels may be cost-prohibitive, or lack the spatial or temporal resolution to sufficiently meet key water modeling, management, and policy objectives. In this study, we demonstrate a fully-automated, open source, low cost wireless sensors network (LCSN) for real-time groundwater data streaming in the South American Subbasin Groundwater Observatory (GWO), located in California, USA. We demonstrate the steps taken to create the GWO, including field, hardware, software, and data pipeline components. The code to acquire and clean data, and render the dashboard are provided online, thus providing a model for automated, low-cost, and real-time groundwater level monitoring.