Water Drip Specular

The left hand image is the full render using the right hand image as a spec map. It seems to me that the water drips should have more shine to them. I think they do not because the wall is a flat surface. I could add bump or displacement based on the drips to force them to catch the light. I suppose if they were real stains on the wall and not running water they would have the same or slightly less specularity than the wall.