WaterCAD does not have the ability to add "pipe fittings" as elements. You can however, model the minor losses for the different fittings (bends, contractions etc.) in the hydraulic model in WaterCAD.
Adding Minor Losses to Pipes
If you wish to add actual pipe fitting components you can explore Bentley's other product AutoPIPE for your piping needs.
Hope this helps.
Bentley Technical Support