Zey, my following application method has worked for the concrete splatter removal, you may find it applicable to water spots also...:
Need:
spray applicator
white distilled vinegar (which you have)
paper towels
Directions: Pour vinegar into spray applicator, and lightly mist the area in repair. You can lay on a small peice of paper towel (or use a whole sheet) on the area your desiring to impove, re-wet the peice of towel by lightly spraying it, make sure the area is saturated, and let soak for 15-20 minutes. Reapply vinegar if it dries. Your trying to get at least 15 minutes of saturation time. You need this time for the acids to dissolve the minerals in the water. This may only soften the minerals so further polishing or compounding may be needed. For concrete platter removal, use a razors edge to gently lift the debris off the painted surface, (You must use extreme caution while doing this, or you may end up digging into the clear coat.....or if its glass, scrape away safely.
Hope this helps, it worked extremely well for the splatter removal, much success !!