This standard is concerned with non-routine microbiological tests for drinking and mineral water and includes detection of pathogenic microbes (faecal streptococci, Salmonella sp., Pseudomonas aeruginosa, Clostridium perfringens, spores of sulfite-reduing, Staphylococcus aureus, Vibrio cholera, Shigella sp. and Leptospires sp.), yeasts and moulds and parasites (Gardia lamblia and Entamoeba histoletica). These tests are used in the evaluation of new sources of drinking water, where there is concern that water might be contaminated with one or more of these pathogenic bacteria or in the case of presence of coliform bacteria in large numbers (more than 16/100 ml), or in periods of diseases’ spread with specific organisms to ensure that the water sources are free from them such organisms. They are also applied according to the desire of the authority in need for such tests.