Here we present new wide range equation of state for water. It has been constructed by sewing together a number of local models describing the matter in different regions of the phase diagram. At the temperatures under dissociation and moderate densities semiempirical equations of state describing water with high accuracy and taking evaporation into account have been used. To construct thermodynamic model describing properties of water in the region covered by shock data Variational Perturbation Theory has been applied. Dissociation reactions have also been introduced in the model. In this region water is considered as a mixture of molecular fluids. Some peculiarities of intermolecular potential for water and their effect upon parameters of shock compression have been investigated. Results of calculation have been compared with experimental data on shock compression of porous ice and snow. At high densities the matter is considered as homogeneous mixture of atoms and Thomas‐Fermi model with quantum corrections and nuclei treatment by Kopyshev is applied. At low densities and high temperatures the model of weakly non‐perfect dissociating gas and Saha model of ionized gas have been used. The EOS has been converted into tabular form to make it efficient when using in hydrodynamic codes. © 2004 American Institute of Physics