Some embodiments may include a water supply system for supplying water based on a predetermined planned daily supply amount of water. While the worries supplied, it may be determined whether a second time has reached after a predetermined time passed from a first time. When it is determined that the second time has reached, an accumulated amount of the supplied water may be measured. A difference between the measured accumulated amount of the supplied water and the planned daily supply amount of water may be calculated. The planned daily supply amount of water may be corrected by adding the calculated difference to the planned daily supply amount of water after the second time. Water may be supplied based on the corrected planned daily supply amount of water.