In the crystal structure of the title compound, C8H8N4O5·H2O, the organic and lattice water mol-ecules are linked together via N-H⋯O and O-H⋯O hydrogen bonds. A C-H⋯O inter-action is also observed between the organic mol-ecules. These hydrogen bonds and inter-actions lead to the formation of a three-dimensional network. An intra-molecular N-H⋯O hydrogen bond also occurs. The dihedral angle between the acetyl group and the almost planar hydrazide moiety [maximum deviation from the least-squares plane is 0.209 (2) Å for one of the nitro O atoms] is 88.5 (3)°.