How To Remove Hard Water Stains From Glass

Living on the ground floor of an apartment complex has been a huge advantage. My 7-year-old son can run out and play with his friends anytime without having to wait for an adult to accompany him in the elevator. But it has its downfall too. The treated water from the lawn sprinkler splashes all over the window panes in the wind leaving ugly hard water stains all over. Well, when life gives you lime, you make lemonade? Well, not me! I rub them on my window panes trying to get rid of those pesky water stains!

Not just lime, over the past two years, I have tried many methods to get rid of hard water stains on windows. Some methods truly suck. But there are some winners too. They can be used on all glasses- be it your window panes or showers. Let’s take a look.

For trying out the various methods, we divided our window pane into 6 sections using paper tape and applied different methods to each section.

Related reading: How To Remove Hard Water Stains From Tap

Method 1: Glass Cleaner

Colin is one of the obvious choices of homemakers for cleaning glass. For this test, we sprayed glass cleaner liberally and scrubbed it with an old toothbrush to dislodge the deposits. Did it work? Not as well as we wanted it to.

When you check its composition, you understand that one of its major components is rubbing alcohol, which doesn’t work effectively on hard water stains. Though it can clean up dust, dirt and shine the glass, its effect on limescale deposits isn’t really impressive.

Method 2: Newspaper

Years ago when we bought a glass-top dining table, the sales representative recommended cleaning it with a wet newspaper to prevent scratches. This method can be used to clean all sorts of glass surfaces like window panes, mirrors, showers etc. Get Set Clean recommends this method for getting rid of hard water stains. So, we tried it out.

We think in the picture, the results look good. But in reality, it wasn’t quite impressive. It cleaned the surface without leaving any lint or residue. But, the hard water stain remained as the newsprint wasn’t enough to get rid of limescale deposits.

Method 3: Vinegar

If you thought high school chemistry was useless, then you might find it immensely useful to tackle various stains and cleaning chores. Hard water stains are caused by calcium, magnesium their carbonates and other salts in the water. They are alkaline in nature. And your best bet to clean them is using acidic cleaners. That is why vinegar proves to be quite effective at cleaning hard water stains. They are mildly acidic with a pH of 2-3. So, it works on mild hard water deposits without harming the surfaces.

For our test, we dipped the toothbrush in vinegar and scrubbed it on the glass. The method requires quite some elbow grease. For larger surfaces, you can do the same with a cleaning brush with long bristles. Ensure they are not too hard as they may cause scratches.

The results were fairly promising. It works the best on milder hard water deposits. But, for heavy deposits, which you typically find at the bottom of the windowpane or shower, it leaves a lot to be desired.

Method 4: Vinegar+ Lime

Many people use a combination of vinegar and lime mixed in 1:1 ratio as they find the smell of vinegar too pungent. But does it work equally good? Yes. Lime too has a pH of between 2-3. It works effectively on milder hard water stains. But, just like vinegar, its effect on heavy hard water stains isn’t the best.

Method 5: Vinegar+ Baking Soda

Vinegar and baking soda are effective cleaning agents when used separately. Many hope to increase the effectiveness by combining it. But, it doesn’t give the same results because when you mix baking soda ( alkaline) and vinegar ( acidic), it results in a neutralization reaction leaving water and salt of the leftover ions.

We tried this method using unequal quantities of vinegar and baking soda to give it the best shot at working. We then scrubbed the paste using a toothbrush. It was able to lift light stains, but we would attribute it more to the vinegar. Baking soda doesn’t really have much of a role as the previous tests with vinegar alone was far more effective.

Method 6: Harpic

Harpic ( Blue) contains 10% Hydrochloric Acid ( HCl) which makes it quite effective at cleaning hard water stains on glass windows, showers, buckets and such inert surfaces. It shouldn’t be used on metals and rubber as the acid may corrode the surface. So, if you are using it on window panes, ensure it doesn’t come in contact with its rubber beading.

As expected, it was the best among the options for stubborn hard water stains. But even so, there were slight stains remaining. Probably leaving it on for a few hours to dry may provide better results.

Being a harsh chemical, take sufficient care while applying it. Use a gloves as it may itch when harpic comes in contact with your skin.

For cleaning window panes, we highly recommend the magnetic window cleaner tool. It is easy to use and fairly effective. You can apply Harpic on the cotton cloth to scrub the surface and the squeegee wipes it clean. But, it tends to leave water streaks on the glass.

So to conclude, use an acidic cleaning agent like vinegar or lime for mild hard water stains on glasses and stronger acidic cleaning agents like Harpic for tough hard water stains. However, when using chemicals, do take sufficient care to protect yourself and avoid damages to rubber beadings surrounding the glass panes.