The FREEWAT platform is a large plugin integrated into the QGIS GIS desktop (http://qgis.org). FREEWAT includes several modules for dealing with water management issues with particular attention to groundwater. Groundwater numerical models (mainly from the MODFLOW USGS family) constitute the basis of the plugin (which also comprises modules for solute transport and density-dependent flow in aquifers). The complete list of so far integrated modules is given below: Observations Analysis Tools (OAT) for time series analysis; Tools for the analysis, interpretation and visualization of hydrogeological data (akvaGIS); Tools for the analysis of groundwater quality issues (akvaGIS); Groundwater flow modelling (based on MODFLOW-2005); Calibration, uncertainty and sensitivity analysis (based on UCODE_2014); Solute transport in the unsaturated zone (based on MT3D-USGS and USB); Solute transport in the saturated zone (based on MT3DMS); Density-dependent groundwater flow (based on SEAWAT); Management of water in agriculture (based on FARM process); Water management and planning (based on MODFLOW-OWHM).