The benzohydrazide mol-ecule of the title compound, C(14)H(11)N(3)O(7)·H(2)O, is planar (r.m.s. deviation = 0.068 Å). The benzohydrazide mol-ecule and the uncoordinated water mol-ecule inter-act through O-H⋯O hydrogen bonds; these together with O-H⋯N and N-H⋯O hydrogen bonds form a three-dimensional network.