I would think the Splendides, having a rather small load capability, would use less water than a stand-alone washer. We use our Splendide all Winter while parked in the Fortuna Foothills of Yuma. But we are parked on a private lot with FHU, so we have access to unlimited water in and out. We don't use the Splendide when drycamping because several loads will just about wipe-out our fresh water tank and fill the gray tank.
Obviously, I am guessing the change to separate washer and dryer units comes with larger load capability. And that would logically mean more water usage per load.