Tony Hartrich
ONLY if you install the optional 64-bit background geoprocessing extension:
10.2.2 -- ArcGIS_BackgroundGP_for_Desktop_1022_140426.exe
10.3 -- ArcGIS_BackgroundGP_for_Desktop_103_141996.exe
If the 64-bit background geoprocessing extension is installed, then you must install the 64-bit .msi of ArcHydroTools. But again that extension is optional -- and most folks will have no issue with 32-bit geoprocessing.