Display Screen or Portion Thereof with a Graphical User Interface for a Water Heating and Treatment System

FIG. 1 is a front view of a first embodiment of a display screen or portion thereof with a graphical user interface for a water heating and treatment system showing our new design;

FIG. 2 is a front view of a second embodiment of a display screen or portion thereof with a graphical user interface for a water heating and treatment system showing our new design;

FIG. 3 is a front view of a third embodiment of a display screen or portion thereof with a graphical user interface for a water heating and treatment system showing our new design; and,

FIG. 4 is a front view of a fourth embodiment of a display screen or portion thereof with a graphical user interface for a water heating and treatment system showing our new design.

The outermost solid line represents the display screen and forms a portion of the claim.