Risk Assessment for Safe Drinking Water Supplies - Global Drinking Water Management and Conservation - page 111

Chapter 6
Risk Assessment for Safe Drinking Water
Supplies

6.1 Introduction

Potable water is considered as a public service, typically supplied by the local
(municipal) public sector. The water supply authority is therefore a public “ utility, ”

such that it charges for water on the basis of being able to break even financially,

whether or not it receives a partial subsidy from a higher jurisdiction. There is an
economic justi cation for treating a water utility as a natural monopoly and hence

as a and not as a private business. There are strong economies of

scale in water treatment and distribution. Consequently, if the water utility were in
private hands, it would have to be regulated not just for health but also for the
protection of consumers against monopolistic pricing. Water utilities in general
have no pro

“ public utility ”

t motive and no incentive to improve water quality or to invest in more
advanced water treatment technologies. In North America and also in Europe, there
are pockets of privatized water companies, but there is no evidence of technological
innovation in such companies and treated water quality is no better than that of the
publicly owned utilities (Dore et al. 2004 ). In general, regulation and consumer
awareness push water utilities to improve water quality and yet provide water at the
lowest possible cost. In North America and many other countries around the world,
the abundant availability of water from lakes and rivers makes surface water an easy
option for water supplies, despite the fact that the quality of most surface water
sources is degraded by point and nonpoint sources of pollution. The presence of
pathogens and chemical contaminants in surface water is the major cause of many
acute and chronic health diseases around the world. Source water quality degra-
dation has led to a number of waterborne disease outbreaks in North America and
elsewhere as documented in Chap. 2 .
In the scienti c literature, there is overwhelming evidence of health risk asso-

ciated with untreated drinking water. But even in treated drinking water, there is a
strong case for introducing some form of risk averseness and risk management. The
objective of this chapter is to review and assess the major types of risk management