3-[(2-Hydroxybenzyl)azaniumyl]propanoate monohydrate

The title compound, C10H13NO3·H2O, is a zwitterion hydrate with the zwitterion comprising a central ammonium group and a carboxylate residue. In the zwitterion, the hydroxybenzene and carboxylate groups are directed to the same side of the molecule and each orientated to place an O atom in a position to form an intramolecular ammonium-N—H...O hydrogen bond, each closing anS(6) loop. The three-dimensional architecture is stabilized by hydroxy-O—H...O(carboxylate), water-O—H...O(carboxylate) and ammonium-N—H...O(water) hydrogen bonds.