Pure water flowing through a pipe of insulating material is electrified. Flowing electrification has been studied using a trough instead of a pipe. The trough has an advantage that the flowing behavior of the water drops on the trough can be observed with the naked eye. The inclination of the trough has been changed in five steps (15°, 20°, 25°, 30° and 35°). Pure water of semiconductor grade has been let flow and electrified. The electrified water has been caught with a Faraday-cage and the quantity of water has been measured afterwards. The charge polarity of water drops was always positive at every inclination of the trough. As the flow rate increases, the charge to mass ratio (Q/M) has gradually decreased. At the steeper inclination of the trough, the more charge quantity in the same flow rate has been observed. When pure water has been supplied at the flow rate of 14.0 ml (about 175 drops) per minute on the trough set at inclination of 35°, luminous emission from micro discharges between the water drops has been observed and recorded as photographs in a dark room. The charge quantity of a drop was 0.96 × 10−9 C. This value is enough to explain the cause of micro discharges between the water drops flowing down the insulating trough.