An Internet of Things system designed for the collection and processing of surface water quality and meteorological data is presented. The open source software architecture is an important aspect of the design of this system, based on common commercial of the shelf components. It integrates: low power microcontrollers and single board computers to acquire and process the data from the most common parameters measured by water quality monitoring systems; long range communications using the LoRaWAN protocol allowing the system to be deployed over large and remote areas; asynchronous and reliable communications; a container based software design for easy, scalable and controllable deployment, thus reducing the complexity of the reproduction of the experimental setup in systems research. This paper also describes the design and implementation of a geospatial database using free and open source software. The system allows the user to visualize and plot the acquired data from the measurement of water quality parameters and meteorological data of various water-bodies at different time periods. Real-time measurements of parameters such as: air and water temperature; electrical conductivity; pH and evaporation, among others, can be correlated with other important properties. Remote sensing data providing real-time information to predict, prevent and act on water quality is also incorporated in the system.