In the title compound, C6H10N6O4, the nitro­amine –NHNO2 substituent and the C–N=N(→ O) unit of the other substituent of the oxadiazole ring are nearly coplanar with the five-membered ring [dihedral angles = 5.7 (1) and 3.0 (1)°]. The amino group of the –NHNO2 substituent is a hydrogen-bond donor to the two-coordinate N atom of the C—N=N(→ O) unit.

The complete molecule of the compound, C6H4N8O3, is generated by a crystallographic twofold rotation axis that runs through the central ring. The flanking ring is twisted by 20.2 (1)° with respect to the central ring. One of the amino H atoms forms an intra­molecular N—H⋯N hydrogen bond; adjacent mol­ecules are linked by N—H⋯N hydrogen bonds forming a chain running along [10-2].

The organic mol­ecule in the title monohydrate, C6N6O5·H2O, presents an almost planar configuration, the greatest deviation from the least-squares plane through the atoms being 0.061 (1) Å for the O atom within the seven-membered ring. Each water H atom is bifurcated, one forming two O—H⋯N hydrogen bonds and the other forming O—H⋯N,O hydrogen bonds. The result of the hydrogen bonding is the formation of supra­molecular layers with a zigzag topology that stack along [001].

Each mol­ecule of the title compound, C12H18N4O6, is located on an inversion centre at the mid-point of the central N—N bond. The azo groups C=N of the Schiff base group have an E conformation and the azo groups in the oxime C=N—O groups have a Z conformation. O–H⋯O hydrogen bonds link neighbouring mol­ecules into infinite monolayers perpendicular to the a axis.