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 an S(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.