Description

The Guidelines for drinking-water quality are intended for use by countries as a basis for the development of standards, which, if properly implemented, will ensure the safety of drinking-water supplies. It must be emphasized that the levels recommended in the guidelines for water constituents and contaminants are not standards in themselves. In order to define standards, it is necessary to consider these recommendations in the context of prevailing environmental, social, economic, and cultural conditions.

Scope

These guidelines are intended to supersede both the European (1970) and International (1971) Standards for Drinking-Water, which have been in existence for over a decade. The main reason for departing from the previous practice of prescribing international standards for drinking-water quality is the desirability of adopting a risk-benefit approach (qualitative or quantitative) to national standards and regulations. Standards and regulations achieve nothing unless they can be implemented and enforced, and this requires relatively expensive facilities and expertise.

Although the main purpose of these guidelines is to provide a basis for the development of standards, the information given may also be of assistance in developing alternative control procedures where the implementation of drinking-water standards is not feasible. For example, the existence of adequate codes of practice for the installation and operation of water-treatment plants and water supply and storage systems, and for household plumbing may promote safer drinking-water supplies by increasing the reliability of the service, avoiding the use of undesirable materials (e.g., lead pipes exposed to plumbo-corrosive water), and by simplifying repair and maintenance.