In the title compound, C(12)H(15)NO(7)·0.5H(2)O, there are two independent mol-ecules in the asymmetric unit, together with one water molecule. The pyran-oside rings each have close to a (1)C(4) chair conformation and the nitro groups are almost coplanar with the benzene rings. The water mol-ecule links the two independent mol-ecules through O-H⋯O hydrogen bonds. All the hydroxyl groups are involved in hydrogen-bond inter-actions, giving rise to a three-dimensional network.