The experimental evidence that chemicals commonly found in drinking water possess carcinogenic properties is reviewed. Three types of sources for chemicals in drinking water are examined; those which are contaminants of drinking water sources, those that arise as by-products of drinking water treatment, and those that arise in the distribution of drinking water. The evidence for carcinogenicity of chemicals that has been obtained from studies employing vegetable oil gavage for carbon tetrachloride, dichloroethylene, trichloroethylene, tetrachloroethylene and chloroform is critically examined. New evidence for the carcinogenicity of acrylamide is reviewed and compared to earlier evidence for epichlorohydrin carcinogenicity. Finally, the relative carcinogenic activity associated with coal tar- versus asphaltic-based paints used in water storage and distribution systems are compared.