Why does hard water come off and sometimes it doesn't? Why do chemicals work and sometimes not?

Hard Water for Dummies

Hard water….. It’s the archnemesis of many homeowners. 

The simple definition of water hardness is the amount of dissolved calcium and magnesium in the water.

Hard water ruins glass, clothing, towels, blankets. It clogs pipes. It plugs up the shower head. 

And it most notably appears on glass as a white/gray scaly substance that is difficult to remove.

Banking soda and vinegar combined make a solution that often works well against hard water. However, sometimes that’s just not the case. 

  • Why is it that the acidic nature of the vinegar and soda works against it and sometimes it doesn’t? 

  • Why do some cleaners work and others do not? 

  • Why does Limeaway work well at one location and not at another?

The reason is simple…. There are 2 types of hard water.  

Calcium Carbonate & Calcium Sulfate

You’re seeing varying results with the chemicals you’re using because there are different sources where your water is coming from. 

Calcium carbonate, or CaCO3, comprises more than 4% of the earth’s crust and is found throughout the world.  Its most common natural forms are chalk, limestone, and marble, produced by the sedimentation of the shells of small fossilized snails, shellfish, and coral over millions of years.  Although all three forms are identical in chemical terms, they differ in many other respects, including purity, whiteness, thickness and homogeneity.  Calcium carbonate is one of the most useful and versatile materials known to man.


Many of us encounter calcium carbonate for the first time in the school classroom, where we use blackboard chalk.  Chalk has been used as a writing tool for over 10,000 years and is a fine, microcrystalline material.  As limestone, calcium carbonate is a biogenic rock, and is more compacted than chalk. 

Calcium carbonate is ACID SOLUBLE which means, acid breaks down the chemical bonds attaching it to the glass and effectively makes your chemical / DIY concoction work as intended. 

Where does your water come from? The city? A well? A river? A lake? The source of your water will determine what’s in your water. 

Well water is susceptible to a huge variety of differing minerals. So a water softener is going to be more of a need than other circumstances. 

CALCIUM SULFATE is NON acid soluble. This means chemicals do not remove the chemical bonds the Calcium has on the glass. Calcium Sulfate is the same material that’s in your sheetrock inside your home’s walls, called Gypsum. Gypsum is calcium sulfate dihydrate (CaSO4 H20). It is a natural mineral that occurs in certain types of sedimentary rocks. Gypsum forms when water evaporates in mineral-rich marine soil environments. Over long periods of time, evaporation brings more minerals to the soil surface, eventually forming a solid deposit.

You can spray vinegar  (insert your favorite chemical here) on it all day long and it’s not going to change. 

If your water comes from an area where CS is prevalent you’re going to have serious hard water concerns that are damaging to your property. 

A water softener is going to deplete faster and any water spots you see on glass will not be easily removed.

It’s the same as spraying sheetrock dust all over your clothes, windows, tile - - - every. single. day.


A razor blade to the glass is your next best option followed by a scratch free abrasive like Steel Wool (Grade 0000). 

If you’re having trouble treating the hard water consider getting a free consultation with one of our expert franchise owners. They will walk you through what to do or even come and help you do it! They can also apply a coating that will minimize the risk of hard water ruining the glass and make cleaning much easier to do. 

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