A water purification system includes: a filter unit having one or more filters for filtering raw water supplied from outside a reservoir having an inlet through which purified water filtered by the filter unit is introduced, having an outlet through which the purified water is discharged, and configured to store the purified water therein and a sterilizing device connected to the filter unit, and configured to sterilize part of the purified water having passed through the filter unit, in a circulating manner, wherein the sterilizing device includes: an ultraviolet ray light emitting diode (UV LED) installed at an inner upper side of the reservoir, and configured to sterilize the purified water stored in the reservoir a circulation pipe installed outside the reservoir, and communicated with the inlet and the outlet so as to form a circulation passage of the purified water stored in the reservoir and a circulation pump disposed at a lower end of the reservoir so as to be connected to the circulation pipe, and configured to circulate part of the stored purified water by providing a driving force to the circulation passage.
