ABSTRACT
Water problems can arise at four different points in the water supply cycle: at the resource, at the treatment stage, during distribution to the consumer's house, and within the household plumbing system (Table 19.1). The problem of pathogens is considered separately in Chapter 20. A problem with quality is defined as a failure of a water supply to meet the minimum standards laid down in the EC Drinking Water Directive or the USEPA national primary and secondary drinking water standards (Section 7.2). However, drinking water should also be aesthetically pleasing to drink in terms of taste, odour, colour and clarity, and on a daily basis, it is these four parameters that consumers use to assess whether their water is fit to drink (Section 17.1). Water supply companies ensure the water that is supplied to consumers is of the highest quality by using a range of management systems. The most important are Water Safety Plans, which are based on a comprehensive risk assessment and risk management approach to every step in the water supply chain to ensure that a water supply is safe for consumption; and Water Security Plans, which use water resources management to ensure adequate supplies on a medium and long-term basis, but also aim to prevent deliberate interference with the water supply chain (Section 21.4).
