How to Remove Hard Water Stains from Glass Windows

Hard Water Stains on windows are unsightly and can be tricky to remove. Hard water has a higher concentration of dissolved minerals than soft water, including calcium and magnesium, leaving a residue that is cloudy and white.

You maybe tempted to use some household products to try and remove the stains, however there are some that are not appropriate. Do not use bleach or other highly acidic substances as this can damage the glass and won’t effectively remove any lime scale. You should also avoid using abrasive materials such as scourers, wire wool, sandpaper, pumice or razor blades to remove hard water stains as these will damage the glass.

This quick guide will show you how to remove hard water stains from glass windows using easily available and inexpensive materials.

Step 1 - Cleaning Your Glass

You should begin by cleaning the glass as much as you can to remove any excess dirt or grime. You can do this with a soft cloth and some warm water with a little soap in it. Do not use hot water as this can damage the glass - particularly if the weather is cold. Glass is extremely sensitive to temperature.

Step 2 - Making the Cleaning Paste

Hard water stains and limescale are alkaline deposits. To get rid of them you should use an acidic solution. There are some that are available on the market in hardware stores. This however is a green alternative.

Make up a paste using 4 tsp of bicarbonate of soda to 1 tsp of vinegar. Depending on how large the area of glass is, you may need to make more paste. Bicarbonate of soda is available in most grocery stores - often found in the baking section.

Step 3 - Cleaning the Glass

Using a soft clean cloth, rub the paste into the areas of the glass that have hard water stains. Rub the paste in a circular motion ensuring that you have covered the entire area. Don't be afraid of rubbing quite hard to start the stain removal process. Leave the paste to work for at least a couple of hours.

Step 4 - Remove the Cleaning Paste

You should then remove the cleaning paste with a clean soft cloth and some warm water, squeezing out the cloth frequently so that you do not rub the paste back onto the glass.

Step 5 - Rinsing the Glass

Finally rinse the glass using a solution of warm water and lemon juice. The lemon juice will counteract any further build up of limescale and also give the glass a lovely shine. If your glass is flat, you can use a window squeegee to do this. These are available from most hardware stores. A squeegee will remove any excess paste and cleaner. It will also remove the water so that you do not get any streaky marks on the glass when it has dried. You can dry the glass finally with a soft cloth or towel.