The objective of this paper was to evalute the performances of various membrane technologies in order to control taste and odor (T&O) episodes. Several membrane processes were evaluated including ultrafiltration (Cutoff of 100,000 daltons), ultrafiltration (UF) combined with powdered activated carbon (PAC), tight cutoff UF (500 daltons), nanofiltration (Cutoff of 200 daltons), low pressure reverse osmosis, and reverse osmosis. Tests were performed on several ground- and surface waters in France and also in California. In most cases, the T&O causing compounds were not identified by conventional analytical procedures such as CLSA-GC-MS, except for the La Carnoye groundwater where dioxanes and dioxolanes were detected in the raw water. Includes 6 references, tables, figures.