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How to Remove Hard Water Spots from Your Automotive Glass

April 15, 2020

How to Remove Hard Water Spots from Your Automotive Glass

You just cleaned your windshield inside and out, and yet you still see small white spots. Or maybe you came out of the car wash disappointed that those little white marks were not removed. What are they? Where do they come from? And what might you do to get rid of them?

Some water is very high in minerals, such as magnesium and calcium. When this hard water dries or evaporates on a surface, it leaves behind a mineral residue. What you see as a result is a haze of white specks that cannot be removed by normal car wash methods. And these spots, or calcium deposits, harden over time. They also give your glass a rough texture. And they are tough to remove.

Hard water spots can come from a variety of sources: your garden hose during a DIY wash, a car wash that does not adequately treat its water supply, or even as a result of the rain.

So, what can you do about them? How might you remove hard water spots from the glass on your car?


Because the minerals in hard water are alkaline in nature, the acid in vinegar can help to neutralize them. Mix equal quantities of water and white distilled vinegar and either put it in a spray bottle and wet the glass, or soak a towel and apply it to the surface. Allow the vinegar to sit on the spots for at least five minutes so that the acidity in the vinegar can counteract the mineral deposits. Then wipe it off with a clean towel until the spots vanish. Repeat as necessary and increase the concentration of vinegar if the stains are stubborn.

Lemon Juice

Like vinegar, lemon juice is acidic and can work against the spots on your auto glass. Fresh lemon juice works better than the bottled variety. You can squeeze the juice from the lemon into a spray bottle or apply with a towel. You can even rub the lemon directly on the glass.

Essential Oils

Essential oils are gaining in popularity for a number of uses. One that you may not have thought of is to confront hard water spots on your windshield. Mix a few drops of lemon or orange essential oil with water, apply to the glass with a towel or sponge, and allow it to soak in for ten minutes. Follow it up with an automotive glass cleaner. Essential oils have the added benefit of protecting your windshield from water spots developing in the first place. Try it once a week to prevent hard water spots from developing in the first place.


A solution of toothpaste and plenty of water can also help remove mineral spots. Apply the pasty solution to the glass, let it sit, and rinse with water, followed by an automotive glass cleaner.

Commercial Products

There are also several commercially available, if less natural, products available to remove mineral buildup. You can find these products at a local hardware store.

Prevention, your best bet

When it comes to hard water stains, the best thing you can do for your car is to prevent them from occurring in the first place. Consider one or more of these preventative measures for your car:

  • Park in a garage or carport whenever possible to avoid rainwater from drying on the surface of your vehicle.
  • Treat any water spots that do develop quickly before they have time to set.
  • Remove residual water from your glass or paint surfaces.
  • Make sure your paint is in excellent condition. Over time, tiny micro-scratches can dull the surface of your paint and hold onto water and dirt. If your paint is entirely smooth, on the other hand, it will repel water more effectively. Consider professional detailing service to restore the lustre to your car.
  • Apply a coat of wax to your paint and treat the windshield with glass water repellant.
  • Treat your windshield (and paint) on a regular basis with water repellant products such as Rain-X Complete Surface Protectant and Armor All ® Extreme Shine Wax at a full-service car wash. If you are a member of a car wash membership, you can make sure your car is treated as often as necessary to prevent water spots.

Hard water spots on your glass can be removed. It is much easier to avoid them in the first place. It just takes a bit of effort – or a frequent car wash add-on service – to keep them from developing on your car.


This article is intended only as a general guidance document and relying on its material is at your sole risk. By using this general guidance document, you agree to defend, indemnify and hold harmless Columbia Auto Care & Car Wash and its affiliates from and against any and all claims, damages, costs and expenses, including attorneys’ fees, arising from or related to your use of this guidance document. To the extent fully permissible under applicable law, Columbia Auto Care & Car Wash makes no representations or warranties of any kind, express or implied, as to the information, content, or materials included in this document. This reservation of rights is intended to be only as broad and inclusive as is permitted by the laws of your State of residence.

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