What is reverse osmosis bottled water?

Bottled water made with the reverse osmosis process is passed through a system capable of removing not only particulates, but also dissolved salts and other impurities too large for filtering. As of 2014, two brands that use reverse osmosis in producing bottled water are Dasani and Aquafina.

Because reverse osmosis systems use a semi-permeable membrane that traps particles as small as 0.001 microns, they can remove chemicals such as fluoride. This creates an advantage over charcoal-based filtration. Reverse osmosis can also be used to produce drinking water from sea water in a process known as desalination. Although it was observed in the 18th century, reverse osmosis was not practical until the 1950s.