General water properties considered. A phenomenological model of water structure has been developed. The mass fractions of the elements of the water structure in a wide range of parameter changes were calculated. Ratio of internal energy, enthalpy, ion product, entropy, heat capacity and other thermophysical parameters with water structure elements is shown. The magnitude of enthalpy is determined not only by temperature, but also by the mass ratio of the elements constituting water. It is proposed to take into account their contribution to the integral isobaric heat capacity, including during phase transition. The change in the structure of water with increasing temperature and pressure determines the minimum specific volume of water at 4 ° C, the characteristics of the behavior of heat capacity, diffusion, sound speed, etc., in the near-critical region.