The detection and quantification of water droplets dispersed in hydrocarbon liquids is of importance industrially, but most notably for quality assurance of products such as diesel and jet fuel. In the present work, a small-scale prototype capacitance-based zone sensing device for the detection of individual water droplets in immiscible liquids is tested. Hydrocarbon liquids containing dispersed water droplets flow through cylindrical holes (diameter = 680 μm) drilled through a printed circuit board (PCB) containing sensing electronics. The exposed copper laminate layer constitutes the sensing electrodes. Dispersions of water in aviation jet fuel, a forecourt diesel fuel and a conventional crude oil have been used in the evaluation. It was found that water droplets of a detectable size to enable measurements to be made with the device (in the approximate range 100–400 μm) were not sufficiently stable in jet fuels, whereas diesel and crude oil were able to suspend water droplets within a size range suitable to permit a simple analysis based on the volume of the spherical segments of the droplet passing through the sensing zone. The results obtained are consistent with expectation based on water concentration and mixing conditions.