Hard water stains or deposits on glass shower doors, windows, and drinking glasses leave the glass looking messy and can even become permanent if allowed to build up for too long. To make matters worse, the mineral deposits can also attract soap and shampoo molecules to create soap scum. Even outside windows can have hard water stains if they are not dried properly after cleaning or if a sprinkler system hits the glass regularly.
Hard water stains appear most often in homes that use well water in areas that have high levels of minerals like lime and calcium in groundwater. Unfortunately, the stains will reappear after cleaning unless the water is filtered or treated with a water-softening system.
Fortunately, if caught early, hard water stains on glass can be kept under control with regular cleaning. While many commercial cleaners will remove hard water stains from glass, mild acids like distilled white vinegar or lemon juice and gentle abrasives like baking soda will remove most hard water stains from glass and can usually be found in your pantry.
How Often to Remove Hard Water Stains From Glass
If you know that hard water stains are a problem in your area, additional care should be taken when cleaning glass fixtures as a part of your regular housekeeping routine. Preventing excessive build-up will protect the glass from becoming permanently etched by the minerals. Once etching begins due to the abrasive nature of the minerals, there is no way to restore the glass to its original clarity.
Equipment / Tools
- Microfiber cloths
- Soft-bristled brush
- Old toothbrush
- Small bowl
- Rubber gloves
- Eye protection
- Old towel
- Distilled white vinegar
- Distilled water
- Lemon juice
- Baking soda
- Table salt
- Commercial hard water stain removers
The cleaning methods listed below get progressively more aggressive in tackling hard water stains on glass. If the first method doesn't remove the stains, try the next one. If you decide to use a commercial hard water stain remover, read and follow the directions carefully. Some cleaners are more powerful than others, so always wear protective gear and store and dispose of the cleaners properly.
Use Distilled White Vinegar
Distilled white vinegar is a mild acid (acetic acid) that will help break the bonds the hard water minerals have formed with the glass surface. You can also substitute fresh lemon or lime juice (citric acid) in the cleaning solution.
Mix a Cleaning Solution
In a spray bottle, combine one part of distilled white vinegar or lemon juice with one part of distilled water.
For a stronger cleaning solution, use cleaning vinegar instead of food-grade distilled white vinegar. Cleaning vinegar contains around six percent acetic acid while food-grade contains around five percent acetic acid and 95 percent water. That doesn't sound like much of a difference, but cleaning vinegar is 20 percent stronger than white distilled vinegar for tackling cleaning chores.
Spray on the Solution
Place an old towel at the bottom of the glass panel to catch drips. Starting at the top of the glass shower door or window, spray the vinegar and water solution across the top of the glass. Move down methodically in even rows until every part of the glass is wet.
Allow the solution to remain on the glass and work for at least 30 minutes.
Scrub and Wipe Away the Mineral Deposits
Using a soft-bristled brush or microfiber cloth, start at the top of the glass panel and wipe away the mineral deposits. Work in a circular motion and rinse out your brush or cloth often. Use an old toothbrush to get into corners or around the edges of metal trim.
While vinegar is non-toxic, wear rubber gloves to protect your hands and eye protection to avoid splatters to the eyes.
Rinse and Dry
Once the hard water stains have been loosened and removed, rinse the glass with fresh water. Starting at the top, use a squeegee to remove most of the water and finish drying completely with a lint-free microfiber cloth.
Use Distilled White Vinegar and Baking Soda Paste
If vinegar alone did not remove the spots caused by hard water, add baking soda as a gentle abrasive. This paste also works well on water-spotted drinking glasses and other glassware.
Spray the Glass With Vinegar
Place an old towel at the bottom of the glass to catch drips. Pour some undiluted vinegar into a spray bottle and starting at the top, spray the entire surface of the glass. Let the vinegar work for at least 30 minutes.
Create a Cleaning Paste
In a small bowl, mix one part of water with three parts of baking soda to create a thin paste. It is usually best to mix the paste in small batches so the paste is not too watery.
Apply the Paste
Using a cloth or scrub brush, apply the paste to the hard water stained areas of the glass. Rub it on in a circular scrubbing motion and always start at the top of the area that needs cleaning and work your way down. If there are only a few stains, dip an old toothbrush into the paste and use it for scrubbing.
Spray With Vinegar Again
After you have applied the paste and it has dried slightly, spritz the area again with undiluted vinegar. You should see some foaming as the baking soda and vinegar react to each other.
Rinse and Dry
When the foaming stops, rinse the glass with clean water and dry with a squeegee or microfiber cloth.
Tips to Keep Hard Water Stains Away Longer
- After showers or when cleaning any type of glass, dry the surfaces completely to prevent hard water spots from forming.
- Use a diluted vinegar solution for weekly cleaning to keep deposits from building up.
- Move sprinklers away from windows to prevent hard water stain splatters.
- Apply water-repellent products to help water sheet off quickly from glass.