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.
Key Takeaways
Use white vinegar to remove hard water stains from glass surfaces like shower doors, windows, and drinking glasses.
For stubborn stains, try an acidic cleaner such as hydrochloric, sulfuric, or phosphoric acid, but be cautious and follow safety guidelines.
For fish tanks, avoid using hard water and chemicals, and clean with vinegar or a specialized fish tank cleaner.
To prevent hard water stains, dry glass surfaces thoroughly after cleaning or rinsing to avoid mineral buildup.
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).
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.
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.
FAQs
Will Magic Eraser Remove Hard Water Stains from Glass?
Magic Eraser is awesome for removing hard water stains from glass. There’s a reason why people refer to them as “magic erasers”: they truly do operate just like magic. They successfully remove water marks from the glass while being very gentle on the surfaces they scour.
It is recommended that you wet the “eraser” before using it and test it out on a surface that is not particularly important to ensure that it will function appropriately.
Does CLR Remove Hard Water Stains from Glass?
CLR is efficient at removing hard water stains from glass. CLR could be used without risk on the glass itself if it was colored during manufacturing rather than being coated or painted after it was made.
It is fine to use CLR in the form of a diluted solution of equal parts warm water and CLR. You have to ensure this solution doesn’t touch the frame of the glass.
Apply this mixture with a sponge or a damp cloth. Remove the solution after two minutes using a sponge or a cloth dipped in cold water.
Can Toothpaste Remove Hard Water Stains from Glass?
Toothpaste can be efficient in removing hard water stains from glass. Aside from glass, it can also remove hard water stains from metal fixtures.
The gentle abrasives in toothpaste that do not come in gel form are designed to clean teeth, but they are also effective for removing stubborn water marks from window glass.
Squirt a minuscule amount of toothpaste onto a lint-free, clean, and comfortable cloth. To get rid of the toothpaste, rub it into the damaged area using the toothpaste, and then use a damp sponge or towel to clean it.
A finish devoid of streaks can be achieved using a squeegee soon after application.
Does Windex Remove Hard Water Spots from Glass?
According to several customers, Windex can remove hard water spots from glass. Some advice is to mix Winder with vinegar and baking soda.
What is the Best Cleaner for Hard Water Stains?
Two natural ingredients work wonders in removing hard water stains: baking soda and white vinegar. Scrubbing stubborn hard water stains using a paste consisting of baking soda plus some drops of water is an effective method.
After applying it directly to the stain caused by hard water and allowing it to sit for a few minutes, remove it with a bristles brush in a circular motion. Pour water over the area for a proper rinse.
A simple mixture of water and vinegar is the most effective product for removing stains caused by hard water.
If you have difficult stains caused by hard water, put some baking soda on top of the vinegar.
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.