2-Ethyl-1H-imidazole-4-carboxyl­ate monohydrate

In the title compound, C(7)H(8)N(2)O(4)·H(2)O, the imidazole N atom is protonated and one of the carboxyl­ate groups is deprontonated, forming a zwitterion. The two carboxyl groups are are approximately coplanar with the imidazole ring [O—C—C—C torsion angles = −176.8 (2) and 2.9 (4)° for one group and −4.6 (3) and 176.4 (2)° for the other] and have an intra­molecular O—H⋯O hydrogen bond between them. The water mol­ecule is linked to the organic mol­ecules via an N—H⋯O hydrogen bonds. Inter­molecular O—H⋯O and N—H⋯O hydrogen bonds are found in the crystal structure.