Water is an inorganic compound because it does not contain carbon. Inorganic matter has geological origins rather than biological. Many minerals are inorganic, although they may have biological origins.
Water would have to contain at least one carbon atom to be considered organic. Many inorganic substances are essential to life. Although it is essential for an organic compound to contain a carbon atom, many compounds are considered inorganic even though carbon atoms are present. The difference between organic and inorganic can be difficult to classify, although carbonates, allotropes of carbon, simple oxides of carbon and cyanides are all considered inorganic by Biology Online's dictionary.