Indicating apparatus of filter exchange period in a water purifier

A system for informing of filter exchange time in a water purifier is provided to maintain water purification performance of the water purifier by early determining whether a sediment filter and a membrane filter are clogged or not by a pressure sensor and informing users of clogging of the filters, thereby exchanging the filters promptly. In a system for informing of filter exchange time in a water purifier comprising a filter part(1) having a plurality of filters for purifying raw water, a water storage tank(6) for storing water purified through the filter part, and an extraction part(7) for extracting water of the water storage tank to the outside, the system comprises: a pressure sensor(20) installed at one side within the water storage tank to detect a pressure of water contained in the water storage tank; a Micom(30) for receiving a signal from the pressure sensor to calculate flow rate of water flown into the water storage tank, and comparing the flow rate of the water that is flown into the water storage tank with a set comparison value; and a display part(40) operated by the Micom to display whether the filter part is closed or not by comparing the flow rate of the water that is flown into the water storage tank with the comparison value. The filter part includes a sediment filter(2), a pre-carbon filter(3), a membrane filter(4), and a post-carbon filter(5). Further, the display part is a monitoring window having a plurality of lamps for monitoring whether the filter part is closed or not.