Why is water not fizzy?

Water, in its pure form at standard temperature and atmospheric pressure, is naturally not fizzy. The effervescence or fizziness in sparkling beverages like soda, beer, and sparkling water comes from the presence of dissolved carbon dioxide gas (CO2).

When water is carbonated, CO2 gas is forced under high pressure into the water, where it dissolves and forms carbonic acid (H2CO3). This reaction causes the release of hydrogen ions (H+), which gives carbonated water its slightly sour taste and lowers its pH. The dissolved CO2 gas also creates tiny bubbles that give carbonated water its characteristic fizzy texture.

In contrast, pure water does not naturally contain significant amounts of dissolved CO2 or any other gas that would cause it to be fizzy. Therefore, unless artificially carbonated, water in its natural state is not fizzy.