Layout & function
One water station per floor
Convenient access to drinking water, no need to go far (no need to go into the kitchen each time): one water station per floor. Leave water lines in + out ready to install a drinking-water purifier later if needed. What else can the water station on each floor combine to become a utility corner (e.g. power and water for the robot, a tap, other equipment)?
Suggestion
Ground floor: a water corner separate from the kitchen - a fixed shelf + table system holding everything related to tea, cakes, water, coffee; placed near the living room or the shared living area. There can be a small coffee-making corner here (optional, no coffee machine bought yet). Upper floors: in the middle of the house, can be placed in the shared living area upstairs.