The equilibrium adsorption of water onto activated carbon is afrequently encounteredphenomenon in the industrial operation of adsorbers. Thissituation highlights a need for amethod of prediction of equilibrium adsorption of water onto activatedcarbon that can be appliedto adsorber models. This study examines an existing method ofprediction of water−carbonand water−organic−carbon adsorption equilibria, making necessaryadaptations such that anew method is evolved, which is suitable for inclusion in an adsorbermodel.