City tap water is generally disinfected and filtered, which is relatively clean and hygienic and suitable for drinking. But sometimes disinfection with excessive chloride will have odor, and the minerals in the water have an impact on the quality of tea. For example, when high-priced iron oxide contains 0.1ppm, the quality of tea soup is not good, and when the calcium reaches 4ppm, the taste will be bitter. When magnesium reaches 2 ppm in the tea soup, the tea soup becomes lighter. In addition to carbon dioxide, purified water basically contains no other dissolved substances. It does not affect the taste of tea when used to make tea, which is beneficial to tea evaluation. Of course, spring water is best for making tea.