How Does A Water Softener Work?

How Does A Water Softener Work?

Have you ever wondered what water softeners are and why we need them? Is your water hard? Do you need a water softener? In this post, we will answer the questions on your mind and more. Ready to find credible answers? Let’s delve right in!

We install water softeners to combat a problem that is surprisingly common – hard water. The U.S. Geological Survey estimates that the water in about 85 percent of American households is hard water – this includes homes that use well water or city water.

Why you may want to bother to use a water softener is this: Hard water is notorious for destroying plumbing and damaging clothes. So what is hard water and what can be done about it? Is your water hard? Do you need a water softener?

What Is Hard Water?

So first things first. What exactly is hard water? 

Generally, one can define water hardness by the concentration of dissolved minerals, especially calcium and magnesium in water. In simpler terms,  you can notice hardness in the water when your drinking glasses have a thin cloudy film on the inside or when your hands still feel somewhat slimy even after washing it with soap and water. 

The reasons for this are not far-fetched. Soap can react with calcium, magnesium, aluminum, etc. dissolved in water, leading to the formation of soap scum. Soap scum is an ineffective complex and hence cannot perform the usual cleansing action of soap. This implies that when you use hard water, you’ll need more detergent or soap to clean anything, be it your laundry, hair, or hands. 

When you heat hard water, there is usually a formation and accumulation of calcium carbonate (as solid deposits) in the water heater. These solid deposits, over time, reduce the fixtures and equipment lifespan and efficiency as well as raises the costs of heating water (because you will require more heat to raise the temperature), clog pipes, etc.

To determine if the water in your home is hard, you can take a water sample from your home to a water-testing laboratory. So, hard water is not only common but can potentially cause serious problems.  Fortunately, there is an effective and relatively affordable solution. To eliminate the hardness in water, you can use a water softener. 

What Is A Water Softener?

Water softeners are filtering appliances that remove calcium and magnesium in water, thereby making the water lose its hardness. The process of removing calcium, magnesium, and some other specific metal cations in water is known as water softening. 

There are several types of water softeners. 

Ion exchange: This water softening process is by far the most prevalent type of water softening process used in homes. An ion exchanger works by removing and replacing calcium and magnesium ions with sodium ions, thereby eliminating the damaging effects of calcium and magnesium. An ion-exchange resin comprises of a large tank with salt pellets in it. This pretty popular and familiar device is most likely what is found in homes that have a water softener.  

Reverse osmosis: This water softening process is a highly efficient process where water flows through a semipermeable membrane. This device filter removes as high as 98% of water impurities. Although it may be quite expensive and consumes a considerable amount of water, a reverse osmosis water filtration system is very effective at removing many chemical impurities, including calcium and magnesium.

Salt Free: This water softening method is often preferred by those seeking to soften their water. Salt free method utilizes a filter and requires no use of chemicals, potassium, or salt. Meaning that minerals that are found in water are not affected. A note of caution though. This method of water softening is not for those with very hard water.

Magnetic: Softer water can also be achieved with the use of magnets. By placing the magnets around the pipes where water is being channeled, the magnetic field will change the composition. The issue with this process is that water hardness levels will return usually after 24-48 hours after being treated by the magnetic field.

How Do Water Softeners Work? 

For this description, the ion exchange water softener will be described as it is the most commonly used. 

Water softeners attract and trap ions that are positively charged, such as calcium and magnesium. As water enters the tank from the top, it passes over the negatively charged beads within the exchange resin in the tank.

As water percolates through these beads, the ions which are responsible for water hardness – calcium and magnesium – become trapped (the negatively charged resin beads attract the positively charged ions, a process known as ion exchange). Consequently, the water that flows from the tank to the house becomes “soft” while the mineral deposits continue to cling to the resin.

What Are The Parts Of A Water Softener?

Typically, water softeners consist of two major parts:

  • A narrow water-softener tank
  • A wide brine tank

The tall, narrow tank is the part of the water softener apparatus that is connected to the line of water supply while the brine tank is connected to the softener tank via a small-diameter fill tube. A discharge hose that is connected to the softener tank then runs to a nearby dry well or drain pipe. 

Inside the softener tank are specially formulated and permanently sealed resin beads filled to the capacity of the tank. The tank that serves to hold brine usually has a lid that you can remove to enable you fill the tank with sodium or potassium chloride pellets when the need for regeneration arises. 

How Does Water Softener Regeneration Work?

Since the mineral deposits cling to the resin, the beads will sooner or later reach a saturation stage where they are at maximum capacity and can no longer attract the cations. When your water softener reaches this point of maximum capacity, then it needs to be regenerated or flushed clean. Now, this is where the brine tank comes in. So what is the water softener regeneration cycle like? 

Here are the water softener regeneration steps. During regeneration, the salty water (brine) which you add to the brine tank will flow up the fill tube, entering into the water-softener tank. This initiates a rinse cycle as the incoming brine water flushes the mineral deposits from the resin beads. Both the mineral deposits and the brine water used for the regeneration process are flushed out from the system via the discharge hose to the drainpipe or dry well. The ion-exchange resin system then becomes “new” again and continues to soften the incoming water. 

How Frequently is Water Softener Regeneration Required?

The frequency with which you have to add salt pellets to the brine tank depends on how much water you use. If you have a family of four, for example, you may need to add one 50-pound bag of pellets per month. The water passing through the tank will no longer become soft if there is no longer salt in the brine tank. 

Usually, there’s a computer located on-board the tank that calculates how much water flows through the softener. The control valve on the water softener usually signals when the resin can no longer attract cations. When its capacity reduces to the level of the preprogrammed setting, the control valve automatically initiates the regeneration cycle. It signals the tank to draw up the heavy brine solution from the brine tank through the resin beads to flush and wash it.

In a water softener catering for a three-bedroom house or a family of four, regeneration usually occurs after every 12,000 gallons of water. The maximum capacity of a softener tank can be preprogrammed using the control valve of the on-board computer. This programming usually depends on the size and number of occupants in a house and the water hardness.

Choice and Amount of Salt For Regeneration

Sodium chloride or potassium chloride can be used for the regeneration process. Regenerating with potassium chloride results in water that has no low sodium content, which is good for people on a sodium-restricted diet. However, sodium chloride is cheaper than potassium chloride. 

Typically, per regeneration, a 1-cubic-foot water softener will require you to dissolve and use about 6-15 pounds of salt in water. If your water contains iron, a higher amount of salt is recommended.

Final Thoughts – Do You Need A Water Softener?

Remember that the benefits of using a water softener are huge. These benefits include but are not limited to the use of less soap for the same cleaning effort, longer lifetime of your entire house plumbing, and elimination of build-up of scales in pipes and fittings. 

If the water hardness in your home is higher than 7 grains per gallon (120 mg/L of calcium or magnesium), then you may need a water softener. You can use a test kit to measure water hardness in your home, send a sample of water to an independent laboratory. Choose credible labs that pass the Environmental Laboratory Accreditation Program. If you get your water directly from the water system in a community, they will be able to supply you with information on the hardness of your water. 


In summary, water hardness is a property of water that is more of a nuisance than a health concern. Water hardness can cause mineral build-up in home fixtures, and also cause the poor performance of soaps and detergents. Depending on the water hardness in your home, you may strongly need a water softener.

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