When we do an import/export with EPANET files the only data that will be retained or unaltered is the data that is supported in both EPANET INP format and WaterGEMS or WaterCAD.
WaterCAD / WaterGEMS exports the EPANET files into .INP file formats. However if you are looking a way to export them as .NET file formats of EPANET then you need to open the .INP files exported from WaterCAD / WaterGEMS into EPANET and export them from EPANET into .NET formats.
Similarly, WaterCAD / WaterGEMS import EPANET models in INP format, so if you have a model in .net format, you will need to first open it in EPANET (free download) then go to File > Export > Network to save to .INP format.
One other thing that happens when importing EPANET files is that two extra pipes are added for every directed node. They are labeled as something similar to "was added during EPANET import". So when the WaterGEMS or WaterCAD model thus created is exported back to EPANET those extra pipes are removed and the original directed node is rebuilt without the extra pipes.
Pumps and valves are seen as link elements in EPANET, whereas WaterCAD and WaterGEMS see them as nodes. Therefore on export to EPANET, a new link element must be created to use as the pump/valve. To do that, two overlapping junctions are created to connect to it. The link in EPANET will have the same name as the pump/valve did in WaterCAD or WaterGEMS. In EPANET, an icon will display for the pump and valve, but when trying to double-click on it, the junction could be selected by mistake.
For Example, take a look the following valve in WaterGEMS/WaterCAD:
Here's what it looks like after exporting to and opening in EPANET:
When hovering the mouse over, it may look as if it's a junction:
However if you click and drag, you'll see its actually two junctions overlapping (at the original location of the valve in WaterGEMS/WaterCAD) with the PRV link element between them:
Troubleshooting problems with importing EPANET or EPASWMM files
Should the EPANET solver and the WaterGEMS solver give the same results for a model?
How are units handled when exporting a WaterGEMS/WaterCAD model to an EPANET model (.inp)?
What are the difference between WaterGEMS/CAD and EPANET?