We use high resolution dynamical structure factor S(q,omega) data measured with inelastic x-ray scattering to reconstruct the Green's function of water, which describes its density response to a point charge, and provides a fundamental comparative model for solvation behavior at molecular time scales and length scales. Good agreement is found with simulations, scattering and spectroscopic experiments. These results suggest that a moving point charge will modify its hydration structure, evolving from a spherical closed shell to a steady-state cylindrical hydration "sleeve".