Hard Water Spots on Windshield

How to Remove Hard Water Spots from Windshield?



Imagine getting your car washed, and you can still see visible water spots on car windows. This could also be due to acid rain or rainstorms wreaking havoc by leaving hard water stains on windshields.


But what is the solution, you may ask?

In this guide, we aim to explain how to remove hard water sports on windshields. You will learn about the causes of water spots that form on windshields, tools and materials needed to remove tough stains, a step-by-step removal process, and preventive measures that must be taken. So, let’s begin!

Causes of Hard Water Spots on Windshields

Approximately 85% of households in America rely on hard water as their only source of water. But how does hard water harm your car’s auto glass?

Groundwater, the major source of hard water, seeps through mineral-rich rock formations and collects magnesium and calcium along the way. When such mineral-rich water comes in contact with your car’s glass screen, it becomes opaque and blurry.

Hence, when hard water is used to wash windshields and left to dry, these minerals leave behind a trace of white spots, also known as calcium deposits or lime scale. If you leave them unattended for a prolonged period, these spots get etched into the glass, and you might have to consider going for a windshield replacement.

A few other causes of water spots on windscreens are:

  • Rainwater droplets
  • Traditional car wash foam
  • Bird droppings
  • Soap residue from car washing
  • Acid rain

Tools and Materials Needed for Removal of Hard Water Spots 

Once you decide to remove the spots, it’s better to be ready with all the required materials. Hence, we have curated a simple checklist that includes safety and cleaning materials.

Safety Materials 

  • Rubber Gloves (to protect your hands from dirt or chemical products, if any)
  • Chemical splash impact safety glasses (protective eyewear)

Cleaning Materials 

  • 1-2 buckets of distilled water (helps remove hard water spots)
  • Spray bottle (to mix solutions)
  • Clean Glassfiber/ Microfiber cloth (preferably closed loop, for cleaning the tough stains)/ Paper towels
  • 2- 3 clean, dry towels (to use after removal of stains and water spots)
  • Squeegee (optional – to wipe out any leftover water)
  • Wax or Sealant or Ceramic Coating (to create a protective layer on the glass surface)

Step-by-Step Process to Remove Hard Water Spots 

To remove hard water spots, you can use any of the methods listed below. First, you should check your windshield’s glass type – whether it is tinted or untinted. If your car has tinted glass, you must be cautious to avoid damaging the film.


With Natural Cleaning Products: Vinegar or Lemon Juice

Step 1: Clean the area of any debris or dust with distilled water. Wipe the surface with a dry cloth.

Step 2: In equal amounts, pour white distilled water and vinegar or lemon juice into a spray bottle. Then, spray the mixture on the hard water spots and let it sit for a minute or two. Once it dries, keep re-spraying.

Note that the alkaline nature of hard water and the highly acidic nature of vinegar or lemon juice neutralize and help remove the stains. 

Step 3: Spray the same solution on one patch of a microfiber cloth and gently scrub the surface of the glass.

Step 4: Use a dry towel to remove the leftover water spots from the glass. Repeat the process If needed.

Step 5: Once dry, apply a protective layer of coating or sealant.


With Commercial Cleaning Products: Glass Cleaners or  WD-40

You will come across various cleaning products and windshield water spot removers available in the market. These products generally contain a combination of wetting and cleaning agents that help remove tough streaks or stains. However, you should read all the instructions carefully before using the product.

Additionally, WD-40 (Water Displacement, 40th formula) is a multi-use product that also helps remove stubborn stains on windshields.


Step 1: Clean the area of any debris or dust with distilled water. Wipe the surface with a dry cloth.

Step 2: Wear your protective eyewear and gloves. Spray a small amount of the cleaning product/ WD-40 onto a paper towel or a microfiber towel.

Step 3: Let the solution settle for a couple of minutes on the affected area.

Step 4: Use another microfiber to wipe out the chemical residue. Repeat the process if needed.

Step 5: Once dry, apply a protective layer of coating or sealant.


  • Check with auto glass experts and only use those cleaning products which are suitable for your auto glass.
  • Avoid spraying any commercial product directly on the auto glass.
  • Use linear motion instead of circular.
  • Start by cleaning the centre of the glass and then move towards the edges to avoid the dirt on the corners from spreading.
  • Drag and clean until the corners to avoid streaks.

Preventive Measures

We have listed a few tips for preventive measures that can be taken to remove hard water spots on windshields or car windows.

  1. Drying Your Car Completely After a Wash Use separate towels for the auto glass and other parts of the car. This will help prevent unattended residue from spreading to any other part of the auto glass.
  2. Cleaning the Windshield Wipers  You need to ensure that you clean the wiper blades regularly or replace them if they are not working properly. Wiper blades that are either worn out or of poor quality might further aggravate the water spots on the windscreen.
  3. Wax, Sealant, or Coating Coatings such as hydrophobic, anti-fog, ceramic, or water-repellent glass sealants or wax help create a protective layer on the glass surface. Hence, these products repel the water from staying on the glass surface by allowing it to flow off the windshield.
  4. Avoid Parking near Water Sprinklers  Water sprinklers often consist of a municipal water supply or a private well and may contain hard water. Hence, preferably park your vehicle at a location that’s far off from the sprinklers to avoid water spots from occurring.

Don’t Ignore the Water Spots for too long. Fix It Soon!

Preventive measures are much better than waiting for the damage to spread throughout the auto glass. Hence, ensure you take utmost care of your car’s windshield for safety and security reasons.

Auto Glass America is a multiservice auto glass company offering services like windshield repair and replacement, car side window repair and replacement, vehicle calibration, vehicle glass repair, etc. Our expert auto glass specialists are trained to repair any damage with maximum care and precision.

Get in touch with us to resolve your auto glass repair and replacement concerns today!

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