What water can't be drunk?
First, aged water: commonly known as "stagnant water", that is, water that cannot be stored for a long time.
2. Thousands of boiling water: Thousands of boiling water refers to the water that has been boiled on the stove for a night or a long time, and the water that has been repeatedly boiled in the electric water heater.
Third, boiler water: boiler water is leftover boiler water such as buns, especially boiler water that has been reused many times, and the nitrite concentration is very high.
Fourth, the water that can't be boiled: the tap water that people drink is chlorinated and sterilized.
5. Boil water again: Some people are used to boiling the remaining warm water in thermos bottles before drinking, in order to save water, coal (gas) and time.