The electrodynamic properties of water are inextricably linked with its structure and molecular dynamics. This chapter discusses a phenomenological approach that provides a microscopic description of the various electrodynamic parameters of water and ice on the same basis. The parameters related to the microscopic dynamics of water (such as the molecular lifetime, the rate of proton exchange, autoprotolysis, and the mechanism of dielectric polarization) are discussed in fine details and compared with those derived from independent experimental data. The microscopic description of the phenomenon of dielectric relaxation and an explanation for the anomalous behavior of dielectric constant are given. In addition, questions on why microwaves are absorbed by water and pass through other dielectrics, and why pH is so dependent on temperature are addressed.