Below you will find our diagram of the water system for the Newmar Kountry Star 3916 KSDP model. You may find that this water system is similar for other floorplans with modifications just for what is changed from the various floorplans. Some of the floorplans have the bathroom components in the same place, so it would be likely to find the same plumbing schematic.
This schematic is as is and may or may not be useful for your coach. There is so little information available online I am sharing this with anyone that may have a use for it in diagnosing their coach.
A PDF version of the schematic is included below.2008-kountystar-3196-ksdp-water-system-pdf