ABSTRACT

In the internationalwater community, the adequacyof a water supply provided for domestic use is often measured using five service indicators: cost, coverage, quantity, quality, and continuity; sometimes referred to, imprecisely, as the fiveCs. Although the scope of each indicator is broad and will lack consensus about their application and evaluation, they are a valuable aid to policy development, concentrating attention upon the factors that are important for the protection of human health andwell-being. For this reason, elements of each of these service indicators can be observed in international and national regulations governing the provision of water for domestic use. Water that is used for other purposes, such as for recreation, may not be assessed using somany indicators, but the requirements

to protect human health and well-being are just as strongwithin the regulations that apply to thesewaters. The indicator that is common between all water

types that impact upon humans is quality: the combination of natural and anthropogenic (arising from human activity) contaminants in the water that define its characteristics. Not all these contaminants are harmful – indeed, some are beneficial – or harmful if present in high concentrations. Understanding where these contaminants enter the water, the factors that control their concentration, how they impact upon human health, how they are measured, and how their concentrations are controlled in the water before and after human contact is an essential pre-requisite for being able to assess and manage the risks associated with contact with water.

SECTION 1 THE WATER CYCLE