Granular activated carbon (GAC) is an effective technique for removing synthetic organics from both ground and surface waters. Questions have been raised, however, over the cost of using GAC in this manner. To provide insight into these cost issues, the Drinking Water Research Division has developed a series of cost curves for various unit processes including those related to GAC. This paper presents a modification of these cost curves into continuous analytic equations. These equations can be used to estimate unit costs for various treatment configurations. Sensitivity analysis can be performed and design configurations listed. Regional options are explored using these equations as the basis for analysis.