Presence of nutrient and organics in drinking water cause microbial growth therein and deteriorate its quality. Water disinfection—a public health measure, is necessary to provide safe drinking water and minimize spread of water based diseases. Disinfection methods such as chlorination, microfiltration, ozonation, UV radiation, and thermal treatment can effectively eliminate the biological (microbial) contaminants alongwith partial elimination of organics. These disinfection methods help in accomplishment of Sustainable Development Goal 6 to ensure availability and sustainable management of water and sanitation for all by 2030. This chapter gives an overview of common drinking water disinfection methods, their action mechanism, the possible formation of by-products and the operative conditions. Further, advantages and disadvantages of disinfection methods have been discussed. For example, Chlorine-based disinfectants may produce by-products which disturb metabolic activities of bacterial cell to remove microbes from water. Ozone is used to decolour, odour control, and elimination of micropollutants. Ozone is unstable in water (with half-life ranging from seconds to minutes depending upon temperature, pH and water quality) and form chemical complex (adduct) with water components that subsequently decompose into highly reactive and short-lived hydroxyl free radicals- (main species of ozonation process). Thermal disinfection methods inactivate the pathogenic microorganisms activity. If disinfectants are not used in sufficient dose, then the formation of disinfection by-products (DBPs) takes place which cause adverse health effects.