Bacteriological analysis of water is for total coliform. There are four methods which may be used by laboratories for the analysis of drinking water for total coliform.
Depending on the method used, the sample analysis could be completed within 24 to 96 hours. These coliform organisms are common inhabitants of the intestinal tracts of humans and other warm blooded animals.
They can be found in topsoil, sewage, ponds, lakes, and other surface waters. The presence of these organisms in your water supply may mean that your drinking water is not properly protected from contamination, which may include human disease causing organisms. Coliform organisms themselves usually will not cause disease.