The suitability of four commonly used nutrient media, and two incubation temperatures for the bacteriological examination of purified water was investigated. The temperature of incubation (22 or 30 degrees C) exerted no profound influence on the observed numbers of colony forming units. Five days was optimal for all incubation conditions. Tryptone Soya Peptone Broth Agar was found to be less productive than the other media investigated, viz. Nutrient Agar 1/8 strength, Nutrient Agar and King A medium, which appeared to be equally productive.