Water pollution has massive impacts on the entire living systems. Water quality is dwindling constantly owing to many reason as growing population leading to demand of industrialization, domestic, agricultural, and other natural causes such as geological and environmental. All these authentic causes have lead water pollution as a serious issue in the current advances. Nanotechnology may deliver technical solution to the water crisis because it may lead to more effective means of filtration that not only remove additional impurities than traditional methods but also faster, more economically and more selectively. Nanomaterials, with their unique chemical and physical properties, such as high porosity and surface area, can be used efficiently for removing toxic metal ions, disease causing microbes, and organic and inorganic solutes from water. Various classes of nanomaterials are also proved to be efficient for water treatment. This chapter will focus on threats to water treatment and recent advances on different nanomaterials with their application in water purification. The second phase of this chapter will focus on carbon nanotubes and graphene as effective material in water treatment. Lastly, this chapter also covers global impact of nanotechnology on human health. © 2017 Scrivener Publishing LLC.