In order to get rid of the water spot, you will need to wet the entire boot. You can then scrub your boots with a mild detergent like wool cleaner. After you are done, you then let them dry and stuff them with newspapers. When the drying process is done, you can brush the boots gently using a suede brush. This helps in restoring the texture of the boots. You can get the detailed process of how to go about it at, http://www.ehow.com/how_6058826_clean-water-stains-ugg-boots.html.