An icemaker appliance includes an ice maker positioned within a cabinet. A circulation conduit extends from a sump to the ice maker. A pump is connected to the circulation conduit such that the pump is operable to flow liquid water from the sump to the ice maker through the circulation conduit. A deionization filter assembly is coupled to the circulation conduit. A sensor is operable to measure a total dissolved solids value of the liquid water flowing through the circulation conduit.