This quantitative proficiency test evaluates your testing ability for the enumeration of Enterococci, Pseudomonas aeruginosa, Clostridium perfringens, Clostridium spp. and Sulphite Reducing Clostridia in drinking water.Microbiological contamination of drinking water sources, with faecal material and soil particles is inevitable and necessitates wholescale treatment to make it safe for consumption. Inadequate treatment, management and storage of the water supplies are the major reasons for waterborne outbreaks. The silver lining is that, in developed countries with modern distribution system, waterborne outbreaks are preventable and FAPAS products could help you to achieve that. The drinking water quality assurance programme covers microbiological monitoring of a range of pathogenic and indicator organisms. Escherichia coli and coliforms are used as an indicator of recent faecal pollution in water samples, whereas the level of Enterococci, which are more resilient in the environment, indicates contamination which may have occurred further back in time.Clostridium is a genus which includes several human pathogens (e.g. botulism, perfringens and tetanus), which cause illness via the production of toxins and are capable of surviving long periods due to the production of bacterial endospores. In the case of botulism and tetanus extremely dangerous neurotoxins are produced and the strains responsible cannot be safely tested for in routine water testing laboratories. Instead, the water is tested for the presence of sulphite reducing clostridia as an indicator of the likely presence and level of clostridia in the sample. Clostridium spp. C. perfringens and sulphite reducing clostridia produce spores which can survive longer than the other indicator organisms and are associated with soil contamination or historical contamination with faecal material. Pseudomonas spp. is frequently found in the environment, in soil, and water as well as the normal intestinal flora of humans and animals. These organisms are not considered as indicators of faecal pollution. Pseudomonas aeruginosa is opportunistic pathogen which have advanced antibiotic resistance mechanism, and it may be associated with serious illnesses in susceptible individuals. Pseudomonas spp. are also associated with the production of biofilms allowing colonisation of pipes with bacterial populations that can cause ‘off’ taste and odour to the water. Proficiency testing activities are important to ensure only high-quality testing measures are used to highlight any potentially unsafe levels of a range of pathogenic and indicator organisms within the drinking water. This can allow you highlight any potential areas of improvement within your testing solution, to maintain the high-quality testing abilities your customers, and regulators, currently enjoy.