The provision of secure drinking water supplies for its citizens is the aim of every government. The quantity of water is in most cases adequate, but the quality in many cases is not. The development of new analytical methods has led to the discovery of new substances of human origin in drinking water. New microorganisms and their toxins pass through the conventional treatment plants to show up in the finished water. What all this means to public health is not clear at present, but it seems that increased vigilance is necessary to provide safe drinking water to all citizens. This text focuses on five major issues: inorganic contaminants, focusing on arsenic and copper; organic contaminants, focusing on petroleum products, insecticides and pesticides; biological and bacteriological problems in raw and finished water and the distribution system; river water watch and surveillance systems; the role of research, the economics of privatization, and the support of international organizations.