Copper-silver ionization is one of the water disinfection technologies employed by releasing copper and silver ions in water for growth control and prevention of dangerous, injurious bacteria, including Legionella. This technology is very active in big water systems and finds application in such situations as hospitals, hotels, and cooling towers. Mechanism of action - *Copper Ions*: Interfere with the cell walls of bacteria; hence, no multiplication of the same. The silver ions act by permeating the bacterial cells and interfering with the DNA and enzymatic functions of the organism. Being an eco-friendly technique, it does not yield harmful by-products, as against the conventional chemical disinfection methods. Copper-silver ionization is independent of the temperature and pH condition of water and for that reason is very reliable in ensuring that the water in even complicated systems is safe.