Disclosed are system and method for filtration capable of minimizing the energy consumption. The filtration system of the invention comprises a processing tank, a first pump for supplying a feed water to be treated to the processing tank, a filtering apparatus in the processing tank, and a second pump for providing the filtering apparatus with a negative pressure so that the filtering apparatus can treat the feed water to produce a permeate, wherein the processing tank is sealable so that the feed water in the processing tank can be pressurized by the first pump after the processing tank is filled with the feed water.