The dielectric constant of water is around 78.4 at ambient conditions. This means that water can allow 78.4 times the charges allowed by vacuum, making it a good solvent for ionic and polar compounds. The dielectric constant is a dimensionless constant that indicates how easy a material can be polarized by the imposition of an electric field on an insulating material. It is the ratio between the permittivity of a medium and the permittivity of a vacuum. The dielectric constant of water is influenced by temperature, frequency, and moisture levels.