All You Need To Know About Water Softeners

How water softeners work

Do you struggle with watermarks on your glassware?

Do you have issues with limescale in your kettle and around your faucet head?

Rest assured, you are not alone. Many households are affected by hard water.

To learn more about hard and soft water, as well as how water softeners work, just keep on reading!

In this article I will discuss:

What is hard and soft water?

Hard water refers to water that has high levels of minerals, especially calcium and magnesium.

Soft water on the other hand has less of these minerals.

There are water hardness testing kits available that you can use to test your water at home.

Little test strips with color changing tips are the most common amongst these. Just dip one of the test strips in the water that needs to be tested, cross reference the color on the tip with the color chart that comes with the kit, and voilà, you know how hard your water is.

The general threshold for water to be considered hard is 7 grains/ gallon, or 120 mg/L.

You could do an easy home test to see if you in fact do have hard water.

Just fill a clean bottle halfway with the water you want to test. Add a few drops of pure liquid soap, and shake.

If many bubbles have formed and the water is clear, you have soft water. If not many bubbles have formed and the water is cloudy, you have hard water.

This test will only tell you if you have hard water or not. You will have to use one of the test kits mentioned earlier to determine the exact level of hardness.

Pros and cons of hard water

The general sentiment towards hard water is that it is bad.

Yes it has it’s cons.

The most prominent is probably the formation of limescale in appliances that heat water. Depending on the hardness of water, the formation of limescale can extend to appliances that work with only cold water as well. The telltale sign of really hard water is the buildup of limescale on your faucet and shower heads.

Limescale is undesirable for obvious reasons. You can read a bit more here on the negative effects of limescale. In short, limescale inhibits heat transfer, causes your appliances to work harder and in the end decreases the lifespan of said appliances.

There are, however, some advantages of hard water. Not excessive hard water, though, just moderately.

One of the main advantages is the calcium, magnesium and iron in that water. The human body needs them. Unfortunately a water softener will remove those minerals. If you decide to get a water softener, consider supplementing those minerals with something else in your diet.

How water softeners work

Water softeners work on a chemical concept called ion exchange.

Some basic chemistry background

Chemical elements in nature are present mostly as compounds. That means that most chemicals like carbon, calcium, sulphur etc. occur as combinations of two or more chemical elements bonded together. An example is carbon dioxide. It is a compound of carbon and oxygen. Another example is water, which is a compound of hydrogen and oxygen. You do get elements on their own, but that is less common.

Calcium and magnesium occur in water in the form of compounds like the ones mentioned above.

Chemical compounds interact constantly and chemical equations explain these interactions.

They would look something like AB + CD = AD + CB.

These equations also go both ways. There is a constant movement in both directions. The side towards which the movement shifts more depends on several environmental factors. These include temperature and pressure.

The chemistry behind water softeners

Water softeners are nothing more than beads of chemical compounds that exchanges their potassium and sodium elements for the calcium and magnesium elements in the compounds in water.

In other words, the calcium and magnesium compounds in the water loses the calcium and magnesium parts to the water softener beads, and the potassium and sodium parts of the compounds in the beads bind to the parts in the water that were bonded to the calcium and magnesium before.

A rudimentary chemical equation would look something like this taking into account the format of AB + CD = AD + CB as explained earlier:


Calcium-Element in water + Sodium-Element in beads = Calcium-Element in beads + Sodium-Element in water


Calcium and sodium is exchanged, calcium gets stuck on the beads in the water softener and sodium gets released into the water as part of the compound formed with the partner element of calcium.

You can replace calcium with magnesium or sodium with potassium in the equations above because both these elements are being exchanged as well.

What are the drawbacks of softening water

Drawbacks of soft water

As mentioned earlier, one disadvantage of using a water softener is the removal of minerals that is needed in anyone’s diet. These are mostly calcium, magnesium and iron. Be sure to check the adequate intake of these minerals when you use a water softener.

Another drawback is the higher levels of sodium in the water after softening. Especially people with high blood pressure should be careful. High levels of sodium in your diet is really bad for you.

Also, the higher levels of sodium will cause more oxidisation (rust) in metal pipes. That rust could come loose and end up in the water.

High sodium levels in water can cause copper to be taken up into the water. If your home has new copper piping, be sure to run water throughout the system as you would normally for at least a few weeks. That will give enough time for a protective layer of minerals to form in order to prevent water taking up the copper.

High concentration solutions of potassium chloride or sodium chloride is used to regenerate the beads. They flush out the absorbed calcium and magnesium. That waste water end up in the drain and can have negative effects on the environment.

High levels of sodium in softened water can be counteracted by using a potassium chloride solution instead of a sodium chloride solution to regenerate the softener beads.

Possible issues with water softeners themselves

Water softeners themselves can also run into some issues.

Water with higher levels of clay or soil particles can clog up the beads and reduce the efficacy of the water softener.

Elements like iron and manganese can clog the resin when they have been exposed to air or chlorine.

Bacteria and fungi can grow on the beads in the softener when the water going to the softener has not been purified first.

All these issues with the softener can be prevented by using a water filtration system installed in front of the water softening system. Such a water filtration system has heaps of advantages as well.

Due to all the above, many people choose to only have certain water supplies in a home softened like laundry hookups, showers and sinks, while others are left unsoftened like cold water taps and water supplies for cooking and drinking.


The decision to use a water softener in your home is entirely a personal decision.

The level of hardness would be the main factor influencing that decision.

In our opinion mildly hard water does not justify installing and maintaining a water softening system. You could adjust the system to compensate for the level of hardness. For mildly hard water the running costs would then be less.

You would still need to buy and install the unit, though.

If you are willing to put up with a bit of limescale in your pipes and water heating appliances, we don’t think it’s worth it.

If, on the other hand, you have really hard water with lots of limescale buildup and elevated electricity bills due to hot water systems not working efficiently, then yes, it would be wise in the long run to invest in a water softening system.

You can read out guide on choosing a water softener here.

Just remember to seriously consider a water filtration system inline in front of the softening system if it does not have an inbuilt one already.