In order to ensure the safety of tap water, and to prevent water from becoming a media for spreading diseases, tap water are processed with a safe amount of chlorine additives, in accordance with the "Drinking Water Quality Standards" (0.2 to 1.0 mg/L). Usually this is not detectable by smell or taste, only more sensitive people will notice it, but it does no harm to our health. Therefore, the slight smell or taste of disinfectant means the quality of water is safe.