Granular activated carbon is commonly used for reducing organics and residual disinfectants from water supplies. This im-proves taste and protects water treatment components such as reverse osmosis membranes and ion exchange resins from possible damage due to oxidation or organic fouling. Typical surface area for activated carbon is approximately 1,000 square meters per gram (m2/gm). However, different raw materials produce different types of activated carbon varying in hardness, density, pore and particle sizes, surface areas, extractables, ash and pH. These differences in properties make certain car-bons preferable over others in different applications. The two principal mechanisms by which activated carbon removes con-taminants from water are adsorption and catalytic reduction. Organics are removed by adsorption and residual disinfectants are removed by catalytic reduction.