Although admittedly effective for removing organic compounds, concerns have been raised about the cost of using GAC for treating drinking water. This paper is devoted to the discussion of the cost of granular activated carbon for removing organic compounds from drinking water. Activated carbon has been shown to be effective for removing a broad spectrum of organics from drinking water (VOC's, SOC's, TOC, etc) but is most effective for removing high molecular weight compounds. The costs developed in this paper coupled with the proper performance relationships should be useful for all of these applications. Extensive cost sensitivity analysis is performed. Several variables are identified as being important. These include choice of system configuration, loading rate and size of system, reactivation frequency, interest rate and design life of system, local construction and operating costs and carbon use rate.