Here's a way to remove water spots from silk

Boil water in a kettle on the stove. Hold the water stained fabric in the steam coming from the kettle (being *very* careful not to burn your hands... you may want to wear oven mitts for this). Allow the fabric to become damp, but not wet. Once it is damp remove it from the steam and rub the stained area with a piece of the same material. Allow it to dry completely and the water stain should be gone.