This part of ISO 9308 specifies a miniaturized method for the detection and enumeration of Escherichia coli (E. coli) in surface and waste water by inoculation in a liquid medium. The method is applicable to all types of surface and waste waters, particularly those rich in suspended matter. This method is not suitable for drinking water and any other type of water for which the guideline is less than 15 counts per 100 ml. This method is not appropriate for enumeration and detection of coliform bacteria other than E. coli.