Arsenic (As) is a naturally occurring element in water, food and air. It is known as a poison, but in very low amount, it is an essential element. The actual problem in the world is As removal from drinking water using modern and alternative technology, especially because EPA and other international standards have reduced MCL from 50 to 10 µg/litre. Because of river and lake pollution, the average concentrations of As in water is up to 100 µg/litre in a number natural water treatment plants. According to MCL, the present technologies are not adjusted for removal of As below 10 µg/litre. A lot of companies were prompted to use alternative technologies and new materials for As removal. This paper describes and compares the conventional and alternative technologies for As removal, bearing in mind complex chemistry and electrochemistry of As and formation of colloidal As, which causes the biggest problems in water purification technologies. The results of using alternative technology are presented as well as the use of a nanomaterial (VALETA H₂O-92) for the removal of As below the MCL value.