A number of chemical contaminants have endangered the quality of drinking water. Realizing the molecular nature of contamination in drinking water, significant progress has beenmade to utilize the chemistry of nanomaterials for water purification. This article summarizes recent efforts in the area of metallic and organic nanoparticle synthesis and the origin of their reactivity at the nanoscale. The application of metallic and organic nanomaterials based chemistry for waste water treatment is summarized for three major types of contaminants: halogenated organics including pesticides, heavy metals and dyes. Besides the above efforts for the removal, as well as ultra low concentration detection of such species, using metal nanoparticles and organic nanomaterial are summarized. Important challenges during the commercialization of nano-based products are highlighted through a case study of pesticide removal using metalallic and organic nanoparticles. Recent efforts in drinking water purification using other forms of nanomaterials are also summarized. The article concludes with recent investigations on the issue of nano size metallic and organic material and its applications for the pollution control.