A water vapor distillation system. The system includes a water vapor distillation device configured to receive a volume of source water from a fluid source and produce distillate, the device comprising: a concentrate flow path comprising a concentrate output; a distillate flow path comprising a distillate output; at least one source proportioning valve; a first heat exchanger comprising at least a portion of the distillate flow path; a second heat exchanger including at least a portion of the concentrate flow path, wherein the first heat exchanger and the second heat exchanger in fluid flow communication with the fluid source; a distillate sensor assembly in communication with the distillate flow path and located downstream the first heat exchanger, the distillate sensor assembly configured to generate a distillate temperature measurement; and a controller configured to control the source proportioning valves, the controller configured to: receive the distillate temperature measurement; determine the difference between a first target temperature and the distillate temperature measurement; and split the source water from the fluid source between the first heat exchanger and the second heat exchanger based on the difference between the first target temperature and the distillate temperature measurement.