In this chapter, water quality of the Incomati basin is described, from snapshot sampling and secondary data of the Department of Water and Sanitation, Water Management System. Water quality parameters and tracers were used to improve the understanding of hydrological processes on the Incomati River basin. Given their physical properties, the use of tracers particularly environmental isotopes Deuterium and Oxygen 18 is an innovative way of studying hydrological processes. Spatial snapshot sampling was used to give an instantaneous picture of the catchments’ hydrochemistry and isotopes over two years, during wet and dry seasons. Furthermore, historical water quality data were explored to understand trends over time of water quality parameters. Results revealed increase of some of the analysed parameters from upstream to downstream of the river profiles.