The organic molecule in the title mol-ecule, C(14)H(12)N(6)O(5)S·H(2)O, is roughly planar with a maximum deviation of 0.156 (2) Å. An intra-molecular N-H⋯N hydrogen bond occurs. In the crystal, inter-molecular N-H⋯O and O-H⋯O hydrogen-bonding inter-actions connect the mol-ecules into a two-dimensional network that lies parallel to (101).