The first WHO publication dealing specifically with drinking water quality, International Standards for Drinking-Water, was published in 1958; it was subsequently revised in 1963 and in 1971 under the same title. In 1984, Guidelines for Drinkingwater Quality was published; its philosophy and content constituted a drastic departure from International Standards.

In 1988, work was started on a new version of the Guidelines. The new Guidelines relies to a great extent on the pioneering concepts of the 1984 edition. The Guidelines are being published in three volumes: Volume 1 was published in 1993, and volumes 2 and 3 will be published during 1995 and 1996, respectively.

• Volume 1, Recommendations, describes the criteria used in selecting the various microbiological, chemical, and radiological contaminants considered; the approaches used to derive the GVs; and brief information supporting the values recommended or explaining why no health-based GV was recommended. 
   
• Volume 2, Health Criteria and Other Supporting Information, is essentially an environmental health criteria document. lt lists the contaminants that were examined, with a view to recommending GVs. Volume 2 elaborates greatly on the health risk assessment of microbial and chemical contaminants and should be considered a vital companion document for volume 1.
   
• Volume 3, Surveillance and Control of Community Supplies, deals specifically with small communities, predominantly those in rural areas of developing countries, and how to control contaminants and their potential risks.