Several methods for rendering and modeling water have been made and a few of them address the natural phenomenon of water droplets flow. As far as we know, none of those methods have used bump maps in order to simulate the flow of a droplet on structured surfaces. The normals of the bump map, that describes the geometry of the micro structured surface, are used in the flow computation of the droplets. As a result, the water droplets will meander down on the surface as if it has a micro structure. Existing models were not suitable for this purpose. Therefore, a new model is proposed in this paper. The droplet will also leave a trail, which is produced by changing the background texture on the surface. This method will not present a physically correct simulation of water droplets flow on a structured surface. However, it will produce a physically plausible real-time animation.