How Does Water Softener Work:Let’s Find Out

How Does Water Softener Work

Water is extremely important in our daily lives. We need to take it for the proper functioning of our bodies, but at home, water is also a tool. It is a fluid medium that many systems depend on, for instance, expelling dirt from clothes and utensils and more. That is because water is very good at holding stuff, either by dissolving it or suspending it.

Unfortunately, this useful tool, unlike most other tools, doesn’t come with a user manual to instruct how to optimize it. That is why sometimes, you will wash your car using seemingly clean water but after a few minutes, you see spots and limescale on the surface of the car, and you wonder where they came from.

It is also the reason why some people spend more money on soap even though they’re using it for ordinary applications. You might also find that your plumbing system is clogged and wonder why it is so even though the water looks clean.

An Explanation for Such Issues

Most of the water we utilize in our homes is sourced from underground. Now, one thing about underground water is that it contains a high amount of minerals, especially calcium and magnesium, which are the most critical agents of water hardening.

You might have heard of the term hard water. This simply means that the water has too much calcium and magnesium, and it is the reason why you’re using so much soap for ordinary cleaning tasks. You can learn how to measure the hardness of your water here.

When water evaporates, it leaves behind the minerals dissolved in it, and that is why you see spots, films, and limescale on items after cleaning them, especially if you let them dry naturally.

The limescale and deposits in your pipes and plumbing systems are also a result of the water containing high amounts of calcium and magnesium. That is why the flow from the taps is slower than usual. If you’re using a water heater, the limescale can reduce its efficiency and life tremendously.

The Solution

As a fix, the calcium and magnesium in the hard water should be removed. Though there are chemicals used for removing these minerals, most homeowners opt for water softeners.

But How Do Water Softeners Work Exactly?

Let’s delve into this matter.

What Are Water Softeners?

Water softeners are devices or substances that are used to soften hard water by removing the minerals that cause it to be hard, that is, calcium and magnesium.

How They Work

There are many positive benefits to water softeners. Typically, water softeners are plumbed into the water supply system of your home, and the fundamental principle they use to soften the water is to take the calcium and magnesium that water contains and give it something else in return, in most cases sodium. The process, as you can see, is some sort of chemical barter trade, and it is known as ion exchange.

At the heart of the softener is a tank, which is filled with resin beads that have active sites containing sodium. These beads carry a negative charge, while the magnesium and calcium in the water carry a positive charge.

The sodium ions in the beads also have a positive charge, and that is why they’re attracted to the beads. However, their positive charge is not as strong as that of the calcium and magnesium ions in the hard water.

Consequently, as the hard water runs through the tank, the positively-charged magnesium and calcium ions are attracted to the beads and having a stronger positive charge than the sodium, they kick sodium out and take its place on the resins. That’s a kind of natural selection, we believe.

The process of exchanging sodium ions for calcium and magnesium ions goes on and on until the beads are saturated with the hard water minerals. At that point, the system enters what is known as a regenerating cycle, which involves 3 phases.

The first phase involves a backwash. In this phase, the soft water flowing from the tank starts flowing in the reverse direction, and by doing so, it flushes dirt out of the tank. Once that is done, the system enters the second phase of the regenerating cycle, which is called the recharge cycle.

You remember that the sodium ions that were on the resin beads were transferred to the water, right?

So now, the beads have to be supplied with more sodium ions, and that’s what the recharge phase is about.

Thus, a concentrated solution of sodium bicarbonate is pumped from the brine tank into the tank containing the beads. The brine tank is also topped up with concentrated sodium bicarbonate to replace the one that was pumped out.

What Types of Regeneration Are There?

As mentioned earlier, the regeneration cycle kicks off when the beads are filled with calcium and magnesium ions. But, that’s not the exact trigger for the process of replacing the sodium ions.

There are two types of re-generations with different triggers depending on the kind of water softener you’re using:

  • Automatic regeneration – an electric timer is installed on the system and you have to set your preferred regeneration routine, perhaps daily at 2.00 am or any other time you’re comfortable with. This is the most popular type of regeneration.
  • Computer-activated regeneration – with this one, a computer monitors the utilization of the resins’ active sites, and when it establishes that there are no more active sites left to accommodate more calcium and magnesium, the computer triggers the process of regeneration.

Apart from the two main types of regeneration, there’s also a less popular system that employs a mechanical water meter to assess water usage and trigger the recharging cycle. A most notable benefit with this kind of regeneration is that you don’t need to install any electrical components, and thus your electrical bill won’t go up.

Again, the recharge cycle is activated only when necessary; when the active sites on the resin beads cannot hold any more hard water ions.

Assessing the Hardness of Water

The hardness of water is typically measured in mg/l (milligrams per liter) GPG (grains per gallon). If you water shows a value of 17.1 mg/l or lower, or 1 GPG or lower, then the water is soft. Water with a GPG rating of 1.1 to around 50 is considered regular.

But when your water has a rating or 60 to around 120 GPG, that is moderately hard water. Anything above that is super hard water that contains a really high amount of calcium and magnesium.

When you buy a water softener, the company will typically give you a free test kit to help you determine your water’s hardness and instruct you on how to use it in the user manual.

Health Concerns

There are no health concerns involving hard water. In contrast, softened water is believed to not be very healthy due to the sodium added. But let us debunk that myth for you.

The sodium added to water as it gets softened is around 20 to 30 mg. Comparing that to the daily recommended maximum intake of over 2000 mg, you can clearly see how minute it is. Besides, if you take a glass of soda or perhaps a glass of milk, you will be taking far more than 30 mg. For instance, a glass of low-fat milk adds more than 100 mg of sodium into your body.

The only people who should be concerned about their health while taking softened water are those who have been diagnosed with conditions like high blood pressure that are deteriorated by sodium or those who are on sodium-restricted diets.

The Types of Water Softener Salts Available

Normally, sodium is put in the mineral tank in the form of sodium bicarbonate.

Here are a few natural salts containing sodium bicarbonate:

  • Solar salt
  • Rock salt
  • Evaporated seawater salt

Which one to choose between the three?

Okay, consider this: rock salt is the cheapest option, but there is more insoluble matter in it. That means if you want to keep your water softener cleaner, you will go for evaporated seawater or solar salt.

The kind of salt you’re going to use should also depend on the softener’s regeneration frequency. Does the softener regenerate only once in a while? Then, evaporated seawater or solar salt should work better for you to prevent the non-soluble matter from building up.

Are you on a sodium-restricted diet? There’s an alternative for you. Rather than using sodium bicarbonate, consider using potassium chloride.

Potassium chloride is a bit more expensive than the other salts but you will not have any concerns about adding sodium into your diet, and again, it is as effective as the other salts. Nonetheless, you should consult the softener’s manufacturer or the user manual before you switch to make sure it will be compatible.

Alternatives to Water Softeners

There are softeners out there designed to prevent the buildup of scale without using salt. In most cases, such softeners don’t remove the minerals causing the water to be hard. Rather, they change the properties of these minerals so that they don’t form any scale in plumbing systems.


Some of the common alternatives to salt-based softeners include the following:

  • Electrically induced precipitation
  • Capacitive Deionization (CDI)
  • Electromagnetic water treatment
  • Nucleation Assisted Crystallization (NAC) or Template Assisted Crystallization (TAC)

According to a study conducted by the WRF (Water Reuse Research Foundation) showed that of the four alternative treatments, the TAC/NAC was the most effective, reducing buildup by more than 90%, which is the same effectiveness that salt-based softeners offer.

How TAC/NAC Softeners Work

TAC/NAC systems contain polymeric beads, which have nucleation sites. These sites change the dissolved minerals into extremely tiny crystals that are insoluble. Being insoluble, the crystals cannot form scale.

The benefits here are obvious – you don’t need salt or water for washing away calcium and magnesium from the beads. You also don’t need energy as there’s no regeneration.

What does it cost to use TAC/NAC systems?

The purchase prices for these systems is comparable to that of the salt-based softeners, ranging from 900 to 1500 dollars for a good home unit. With a salt-based unit, you have to replace the salt frequently, and you could use 120 to 250 dollars per year on that. TAC/NAC systems don’t need as much maintenance, and you only have to replace the media once in every four years.

The replacement will cost you about 250 to 850 dollars, and by dividing that by four, you can see that’s an annual cost of around 62 to 212 dollars.

Compare that with the yearly maintenance cost for the softeners, and you will see that TAC/NAC softeners are slightly cheaper.

Keeping in mind all the effort put into adding salt into salt-based softeners now and then, and the fact that TAC/NAC softeners are install-and-forget systems, we all can agree that latter is more convenient.


1. Is drinking from a water softener safe?

The main concern surrounding drinking softened water is the one about the sodium added to the water. The daily recommended intake for sodium is up to a maximum of around 2500 mg and considering that the amount of sodium a water softener adds is usually up to 30 mg per glass, it is highly unlikely that the softened water will affect you. after all, a glass of softened water contains less sodium than a glass of low-fat milk, which could contain more than 120 mg.

The only time you should be concerned about your safety while taking softened water is when you have been diagnosed with a condition that requires you to take a sodium-restricted diet.

2. How full should my brine tank be?

Normally, it is recommended that you keep your water softener’s brine tank at least ¼ full always. For highest efficiency, the level of the brine shouldn’t be more than 6 inches beneath the tank’s top.

3. How much would I need to set up a water softener?

You have to options – you can either go for a manual regeneration softener or a metered one. A manual regeneration system goes for around $400 with an additional 100 to 400 bucks for installation. A metered softener is more expensive, going for around $3000.

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Final Thoughts

Here are the key takeaways: a water softener works through ion exchange, which involves taking calcium and magnesium ions from hard water and giving sodium ions in return. The sodium that is transferred to the water is not in the form of common table salt but rather in the form of sodium bicarbonate, and thus the softened water is only very slightly salty.

If you feel a water softener will be beneficial for your home, check out our best water softener reviews.

A bonus takeaway: water softeners do not remove dirt and debris from hard water or any harmful chemical like chlorine or pesticides; it only removes the elements causing the water to be hard, that is, calcium and magnesium. If you want to remove contaminants, consider incorporating a water filter into your plumbing system.

Last update on 2021-05-14 at 23:15 / Affiliate links / Images from Amazon Product Advertising API


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