The drinking water access is fundamental for the health, one of the basic human rights and a component of the effective policies of health protection. The present volume of the “Guides for quality of drinking water” describes the requirements for the water salubrity, like minimum procedures and the specific reference values, and the way in which they must be applied. The volume also describes methods to determine the directives, including the reference values. It includes information sheets on significant microbiological and chemical dangers. The elaboration of the present third edition of the “Guides for quality of drinking water” includes a revision in depth of the methods to guarantee the microbiological innocuousness. The Guides are aimed to people in charge of regulation and elaboration of policies in the matter of water and health, and to their advisers, to guide them in the elaboration of national norms. Many other people use Guides and documents like source of information about the water and health quality, as well as on effective management methods.