What is a Geotable?
A GeoTable is a special type of Flextable that determines which fields (attributes) are included in the WaterGEMS, SewerGEMS or HAMMER geodatabase when working inside the ArcGIS platform. ArcMap interacts directly with an intermediate personal geodatabase (MDB file) associated with the hydraulic model, not the hydraulic model database (.wtg.mdb or .wtg.sqlite). The fields selected in the GeoTable are the fields linked between the hydraulic model database and the geodatabase. ArcMap can then apply symbology effects from the available geotable fields.
The GeoTables have their own separate section in the Flextable manager:
WaterGEMS for ArcGIS FAQs
SewerGEMS for ArcGIS FAQs