Fecal coliforms suspended in a natural stream water were exposed to rhodamine WT dye, chlorine and both in combination. Samples were analyzed for coliforms by three enumeration techniques. Statistical analyses of data by the paired-t test showed that for non-chlorinated samples no significant difference (0.10 level) was found between the recoveries by the three enumeration techniques. For chlorinated samples the standard membrane filter technique (Std-MF) yielded significantly lower recoveries (0.05 level) than the standard MPN procedure. A modified membrane filter technique employing a two-layer agar and a five hour 35°C preincubation period (Mod-MF) was found to yield recoveries consistently greater (0.05 level) than the standard MF technique. The data showed that exposing fecal coliforms to 100 to 1,000 ppb of rhodamine WT dye for 30 minutes, did not inhibit the recovery or enumeration of the organisms by any of the three assay methods. The number of fecal coliforms that survived exposure to 0.2 to 0.3 ppm of chlorine and 10 to 100 ppb of dye was not significantly different from the number enduring contact with similar concentrations of chlorine alone. / Master of Science