This chapter describes the enumerative techniques for total coliform bacteria in water and wastewater. The method chosen depends upon the characteristics of the sample. The coliform or total coliform group includes all of the aerobic and facultative anaerobic, Gram-negative, nonspore-forming rod shaped bacteria that ferment lactose in 24 to 48 h at 35°C. The total coliform test can be used for any type of water or wastewater, but since the development of the fecal coliform procedure there has been increasing use of this more specific test as an indicator of fecal pollution. Dehydrated media used for detection and enumeration of total coliform bacteria are DICFO M-Endo broth membrane filter (MF) (No. 0742) and BBL M-coliform (MC) broth (No. 11119), or equivalent. Environmental sources, such as vegetation, paper mills, textile production, sugar cane, and farm produce contribute 71 to 88 percent of all Klebsiella in the total coliform population.