Assurance that drinking water is microbially safe has traditionally been determined by measuring bacterial indicators of water quality, most commonly total coliforms and E. coli. This chapter addresses four questions. i. Should we continue to rely on these? ii. Are these indicators sufficient to ensure microbial water quality? iii. Should we adopt a more holistic approach? iv. We have our risk management systems, our drinking water safety plans; does this mean that we could comfortably move, by focussing more on risk management, away from our reliance on end point testing? Total coliforms have been shown to be a poor parameter for measuring the potential for faecal contamination of drinking water due to their presence as natural inhabitants of soil and water environments, their ability to grow in distribution systems and their inconsistent presence in water supplies during outbreaks of waterbome disease. All these points make it difficult to interpret the sanitary significance of their presence (in the absence of E. coli) or have confidence in water quality in their absence.
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