An airborne exploration system used with an aircraft for exploration of oil and gas, mineral deposits and aquifers. The survey system uses natural electromagnetic EM fields as an energy source. The exploration system includes at least one non-directional, wideband, total electric field, water sensor. The water sensor includes a water container filled with water and adapted for mounting on an aircraft. The water container has a pair of conductive metal bands mounted around opposite ends thereof. The metal bands provide a capacitive electrical coupling with the water in the container. The water container has a diameter substantial the size as a length of the container. Therefore, the sensor responds to an electric field substantially independent of the relative orientation of the electric field. The bands are electrically connected to a computer data processing unit mounted on the aircraft. The data processing unit is used for receiving and processing valuable and anomalous electric field data from the water sensor when flying over a potential oil, gas or mineral prospect.