Abstract: A method and apparatus for determining the water content and its conductivity in porous media such as soils. The apparatus uses radio frequency electromagnetic fields to sample the environment of a sensor probe. One configuration uses an active oscillator including a sensor probe whose frequency of oscillation reflects the composite dielectric properties of the porous material in the vicinity of the sensor probe. A method which uses two sensor probes operating at different frequencies allows a quantitative determination of the water content and its conductivity. The apparatus has various configurations which allow it to evaluate fluid content in either unconsolidated or consolidated porous materials.