Water is the most vital substance in every aspect of life, and its contamination because of the activity of mankind poses a big global challenge. Addressing this issue for drinking purposes and environmental protection is the current big issue. Many research groups worldwide have been working on effective treatment technologies based on nanomaterials during the last two decades. Water and wastewater treatment by nanomaterial-based technologies has become an aid in finding possible solutions for contaminated wastewater released from various water sources. Nanoscale materials can be seen to take on unique and unpredictable properties that make them more robust, flexible, lighter, and faster, and the particular material used for the development of devices and systems.