5-Carb-oxy-2-isopropyl-1H-imidazol-3-ium-4-carboxyl-ate monohydrate.

In the title compound, C(8)H(10)N(2)O(4)·H(2)O, the imidazole N atom is protonated and one of the carboxyl-ate groups is deprotoned, forming a zwitterion. An intra-molecular O-H⋯O hydrogen bond occurs. The crystal structure is stabilized by inter-molecular N-H⋯O and O-H⋯O hydrogen bonds.