There are water stained marks on the mirror in my bathroom, is there any way to remove these stains?
Water should not stain mirror unless you have white marks. Dish soap and a soft dish scrubber should remove it. The only other thing it could be is hair spray overspray. Same thing though...use a little effort to use a plastic dish scrubber. It will not hurt the mirror as it is made of glass.
I use vinegar on mirrors and glass and find it cleans well and leaves them streak free
If "standard" cleaners such as vinegar have not removed it, try Barkeeper's Friend. Just don't let your water, etc. drip behind the mirror edges or it will ruin the backing.