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How to Remove Hard Water Stains from Glass

Updated
Say good-bye to the grime on your glass.

Hard water stains appear when hard water is evaporated from a surface and leaves behind mineral deposits. These same minerals often cause limescale and other buildups in your plumbing and appliances.

The marks left by hard water aren’t dangerous and aren’t always obvious. However, they can be very visible on glass surfaces, which is why drinking glasses often appear hazy or cloudy even after cleaning them.

Removing these stains can be difficult if you don’t know how, especially when cleaning delicate glass objects. In this article, we will tell you how to remove hard water stains from glass shower doors, windows, drinking glasses, and even fish tanks.


Shower Doors

Modern shower doors are designed to encourage water to flow off their surfaces as quickly as possible. However, in time, hard water droplets can begin leaving marks and these spots can make an otherwise pristine shower door look unsightly.

There are two simple ways to get hard water stains off glass shower doors, one natural and one chemical:

  • White vinegar
  • Acidic cleaner

Method 1: Vinegar

White vinegar is a popular glass cleaner for shower doors as it is a natural solution, thus less toxic. Many people already have it in their homes, making it a quick and convenient solution. It is also usually cheaper than chemical cleaners.

Warning

Be careful when using white vinegar near hardwood or stone flooring, as its acidic properties can damage the finish (1). White vinegar is safe to use with the majority of flooring types.

What You Need

Before you clean your shower door with white vinegar, make sure you have these items:

  • Clean cloth
  • Spray bottle
  • Sponge
  • Microfiber cloth/towel
  • White vinegar
  • Baking soda

Step 1: Clean the Glass

Begin by wiping the door with a damp cloth to remove any potential dust or dirt particles. This will make it easier to remove the stains and avoid streaks later.

Step 2: Mix the Solution

Combine equal amounts of water and vinegar in a spray bottle. If the stains are stubborn, you can increase the amount of vinegar to make the solution more potent.

Because hard water is alkaline, an acidic cleaner such as distilled white vinegar is highly effective at dissolving the minerals it leaves behind. The acidity neutralizes the alkalinity and dissolves the stains (2).

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Step 3: Apply the Solution

Spray the solution onto the obvious stains and then spray the entire door. Leave it for five minutes to allow the vinegar to react with the marks. Most of the solution will drip down the glass but some of it will stick to the stains.

Apply the solution to a sponge and wring out the excess, leaving it damp. Use it to smear the vinegar solution all over the door. Pay close attention to lower corners and close to the rim — these are common areas of buildup.

Step 4: Make a Paste

Create a paste by mixing equal parts baking soda and white vinegar. Dip a sponge into the mixture and apply it to the stains using circular motions.

Step 5: Rinse

Rinse the door with warm water. You can use your showerhead for this. If you notice any stains, use the sponge to give them a quick scrub while rinsing.

Step 6: Dry the Glass

After cleaning and rinsing, it is important to dry the glass using a cloth (preferably microfiber as it won’t leave streaks). Drying the door is essential to prevent new stains from appearing. If you still see significant staining after drying the door, repeat the previous steps.

Take Note

This method also works well on mirrors!

Method 2: Acidic Cleaner

If you have more stubborn hard water stains or scale deposits on your shower door, you might need to use an acidic cleaner instead.

What You Need

  • Personal protective equipment — rubber gloves, plastic apron, and mask
  • Acidic solution — hydrochloric, sulfuric, or phosphoric acid
  • Spray bottle
  • Clean cloth/sponge for cleaning
  • Clean cloth/towel for drying

Step 1: Get Protected and Ventilate

These acids are highly abrasive and can cause significant damage if they touch your skin. They can also produce toxic fumes, so stay protected and wear thick rubber gloves, a plastic apron, and a mask. Keep the room ventilated to allow fumes to escape (3).

Protect Your Floors

If you have natural stone flooring, cover it with a thick plastic sheet to prevent damage. Even natural acids such as vinegar can etch natural stone tiles (4).

Step 2: Choose a Product

For heavy buildups of hard water stains, you will need something stronger than vinegar. Choose a strong acidic product such as hydrochloric, sulfuric, or phosphoric acid. These are very powerful cleaners and will be able to break even thick mineral deposits.

Step 3: Use as Directed

Dilute the acid as directed on its label. It is a good idea to put it in a spray bottle — this will make it much easier to apply. Apply the solution by following the instructions. Allow the product to work for a while if necessary, or wipe it off immediately with a cloth or sponge.

Step 4: Rinse and Dry

After cleaning the door, rinse it thoroughly with clean water. This is particularly important with acidic cleaner as it can damage the glass if left on the surface.

Don’t forget to dry the glass after rinsing it to prevent further stains.

Glass Windows

Again, we prefer to use white vinegar to clean glass windows if possible. A chemical cleaner should only be used to get hard water spots off glass windows if natural cleaners don’t work.

What You Need

  • White vinegar
  • Salt
  • Baking soda
  • Mixing container
  • Spray bottle
  • 2 x Clean cloth/sponge
  • Clean microfiber cloth

Step 1: Apply Vinegar

Mix equal amounts of water and white vinegar in a spray bottle, then spray it onto the stained window. Rub the solution into the affected area using a damp cloth or sponge, then leave it to work for up to 30 minutes.

If the stains are particularly hard or stubborn, use undiluted vinegar instead.

Step 2: Make a Paste

Combine equal amounts of salt and baking soda in a container or bowl, then add small amounts of water to form a paste. You can use any type of salt for this, but fine table salt is usually easier to work into a paste.

Step 3: Apply the Paste

The combination of baking soda and salt will create a mildly abrasive cleaner that should cut through tough stains.

Dip a cloth or sponge in the paste and rub it onto the window using circular motions. You won’t need to apply too much pressure as the baking soda and salt will do most of the work for you.

Step 4: Rinse and Dry

Rinse the area thoroughly using a damp sponge or cloth. Try to remove all of the paste to avoid creating any extra marks.

Finish by polishing the window using a clean microfiber cloth to ensure no water is left behind to stain the window again.

Drinking Glasses

Drinking glasses are more delicate than modern shower doors and windows but they can still be cleaned thoroughly using our favorite natural treatment. Even better, you can simply put them in a dishwasher if you have one.

Method 1: Vinegar

What You Need

  • White vinegar
  • Distilled water — tap water is fine if you can’t get distilled
  • Spray bottle
  • Clean dishcloth/towel
  • Clean two-sided sponge
  • Clean microfiber towel

Step 1: Mix Vinegar and Distilled Water

Start by combining equal amounts of water and white vinegar in a spray bottle. You can use tap water if you don’t have distilled. However, distilled water is free from any hard materials such as minerals, so it won’t create new stains (5).

Step 2: Set up the Glasses

Place a folded dish towel or cloth on a flat surface. Place each glass on the towel — if the hard water spots are on the inside, keep the glasses upright to allow easy access.

Apply the solution by spraying the spots. Leave the glasses for a couple of minutes while the solution works.

Step 3: Scrub

Take the soft side of a two-sided sponge and wet it with the vinegar solution. Rub the stained area gently to remove the mineral deposits. If the stains are stubborn, turn the sponge over and wet the rough side — then scrub the area carefully.

Step 4: Rinse and Dry

Once the stains are gone, rinse the glasses thoroughly. Give them a gentle shake over the sink to remove any excess water, then wipe them dry using a clean microfiber towel.

Method 2: Dishwasher

  • Temperature: If you often notice hard water stains on glasses after using your dishwasher, you can try adjusting your settings. One trick is to lower the water temperature. This is not only better for the environment, but it will also prevent minerals from forming scale. High temperatures harden minerals and create scale, which is why kettles gain so much scale from boiling water (6).
  • White vinegar: An excellent way to combat hard water stains is by adding a ¼ cup of white vinegar to the rinse cycle. Open the compartment immediately before the rinse cycle begins and pour in the vinegar. The acid will break down hard minerals and prevent them from staining your glasses (7).
  • Rinsing agent: A reliable way to prevent hard water stains is by adding a rinsing agent to the dishwasher — such as Finish Jet-Dry. These are automatically released during the rinse cycle and help the dishes to dry without stains.

Glass Fish Tanks

If you have an aquarium and want to avoid the telltale signs of hard water, here are some important tips:

  • Avoid hard water: Avoid using hard water in the tank because of its hard mineral content. Experts say it takes longer for fish to adapt to hard water. Also, as the water slowly evaporates, it leaves behind limescale or mineral deposits (8).
  • Don’t use chemicals: Resist the urge to clean your aquarium with chemical cleaners that you use elsewhere in your home. These can leave a residue that is lethal to fish — even on the outside of the tank. It is best to visit your local pet shop and choose a recommended fish tank cleaner.
  • Vinegar works: If you want to clean your fish tank using a natural method, vinegar is perfectly safe. It is highly effective at removing stubborn limescale and is also a natural disinfectant. However, you will need to place your fish into a holding tank first. Drain and empty the tank, then scrub the tank and any decorations using the vinegar solution.
  • Algae scraper: You can use an algae scraper or razor blade to remove very tough stains. However, avoid using razor blades on plexiglass as they can scratch the surface.

Whenever cleaning a fish tank, make sure you rinse and dry the tank properly before refilling it and replacing fish, rocks, and decorations.


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About the Author

Sylvia Jones

Sylvia Jones is a hands-on, DIY aficionado from Indiana. She is passionate about home improvement, gardening, and environmental conservation. In her spare time, you can find Sylvia getting involved in home improvement projects around the house with her husband, or spending quality time out in the yard.