To download and install Arc Hydro tools for ArcGIS 10.7, you should use the official Esri distribution channels. These tools are free but require an existing ArcGIS software license. Official Download Sources
To add the specialized toolbox to your ArcToolbox window, right-click "ArcToolbox," select "Add Toolbox," and navigate to C:\Program Files (x86)\ArcGIS\Desktop10.7\ArcToolbox\Toolboxes . download arc hydro tools for arcgis 10.7
To verify that Arc Hydro Tools has been successfully installed: To download and install Arc Hydro tools for ArcGIS 10