Abstract
In the zwitterionic title compound, C18H16N2O4 center dot H2O, the dihedral angle between the planes of the benzene and indole rings is 39.20 (8)degrees. An intramolecular N-H center dot center dot center dot O hydrogen bond generates an S(6) ring motif. In the crystal, intermolecular hydroxy and water O-H center dot center dot center dot O(carboxylate) and N+-H center dot center dot center dot O(carboxylate) and indole N-H center dot center dot center dot O(water) hydrogen bonds give a three-dimensional structure.