The present disclosure relates to a method and device for obtaining distillate from non-potable water. The method comprises the steps of utilizing solar power from a solar power system to produce electricity and steam, utilizing the electricity and the steam in a water treatment device to convert the non-potable water into distillate and concentrate, transporting at least a part of the distillate to consumers for use. The method and device provide multiple effect distillation (MED) combined with vapour compression (VC) being able to work 24 hours a day only on solar energy.