Thin-layer Chromatographic procedures for the determination of phenol and certain substituted phenols are applied to raw surface waters. Both water grab and carbon adsorption samples are analyzed. The concentrated solvent extracts of the samples are chromatographed on silica gel G thin layers and developed in benzene/cyclohexane/diethylamine (5:4:1) or chloroform. The first system provides for selective determination of the alkylphenols, since the chloro-, nitro- and aminophenols remain at or near the origin. Phenols developed with this system are detected with p-nitrobenzenediazonium fluoroborate. Those developed with chloroform are detected with Gibbs' reagent. Specific phenols are characterized by their Rf values and the color of the spots produced. A wide variety of phenols are detected at the 0.1 to 10 μg level with the Gibbs' reagent and at the 0.5 to 25 μg level with p-nitrobenzenediazonium fluoroborate.