To clean water-stained windows, use a mixture of equal parts water and white vinegar. Apply the solution to the stained areas and let it sit for a few minutes. Scrub with a sponge or cloth, then rinse with clean water and wipe dry to remove stains. For stubborn stains, a commercial cleaner may be needed.

Use vinegar solution, apply, scrub, rinse, and dry to remove water stains.