Drinking water standard: (1), water is transparent, pollution-free, impurity-free, odor-free, and tastes good. (2) Moderate hardness. The so-called hardness is the total amount of salts such as calcium and magnesium in water. The more calcium and magnesium, the harder the water quality, and vice versa. Most people think that the hardness should be in the range of100-170 mg/L. (3) It contains appropriate minerals and trace elements, and requires a certain amount of soluble total solids in water. The so-called dissolved total solid is the solid residue obtained after water samples are filtered and dried, including the total amount of all substances dissolved in water, such as inorganic mineral components. The ideal index of the general population is 300 mg/L, and people who need to supplement more minerals are better. What should I pay attention to when drinking bottled water? (1), drinking fountains should generally be placed in a cool and dark place, not in direct sunlight, so as not to breed green algae. (2) Open bottled water should be drunk within 2-4 weeks in autumn and winter, preferably within 7- 10 days in spring and summer. Too long time is easy to increase the total number of colonies. (3) Don't power on the water dispenser for a long time. Repeated boiling will affect the water quality. (4) Used empty barrels should be put in a clean place. Don't pour dirty water or throw garbage (such as cigarette butts) into it, otherwise it will bring difficulties to the cleaning and disinfection of the water plant. (5) The water dispenser should be disinfected regularly, preferably once a month in spring and summer and once every two months in autumn and winter, otherwise it will cause secondary pollution. Remember!