How A Water Softener Works

Water softeners are manufactured with different filtration and softening processes, depending on the choice of the customer. The more complicated the processes, the more expensive the water softener. A softening unit with the simplest filtration procedure is probably the most economical among households.

A water softener simply operates on a very simple principle – the calcium and magnesium ions found in the hard water are switched to more desirable ions like sodium. This ion exchange eliminates the dilemma of having hard water as sodium does not precipitate in the plumbing fixtures and to any water-related appliances, and does not react to the use of soap and detergents.  

The amount of sodium in the ion exchange varies on the model of the water softener, but the Food and Drug Administration has set a standard of mounting to the amount of less than 12.5 milligrams per eight ounces. Only a minimum quantity of salt can suffice the needs of the ion exchange process in the softener. Too much sodium can lead to health risk, and this is a health concern that all household with salt-based water softeners should take notice. 

The ion exchange is performed in the resin tank that is full of small polystyrene beads or resin orzeolite. The resin beads are negatively charged and they are bonded to positively charged sodium ions. When water flows through the beads, the sodium then switched places with the hard minerals or calcium and magnesium ions. 

There are questions that have been raised as to why load salt into the water softeners when the resin beads are doing all the work? After numerous iteration of cycles, the calcium and magnesium ions have already been replaced with sodium ions in the beads, thus making the beads ineffective to convert hard minerals. An ineffective operation of hard mineral conversion leads to ineffectual softening process in the unit. That is why the salt-based water softeners are incorporated with a regeneration cycles that can let the resin beads get soaked up in a strong solution of salt and water or brine. A complete amount of sodium in the brine solution makes the hard minerals in the beads to give way, causing time for the beads to recharge with sodium. After the regeneration process, the water softener then automatically flushes the remaining brine solution, together with the collected calcium and magnesium ions, through a drainpipe. The regeneration process creates around 95 liters or 25 gallons of salty water. 

A “Demand Initiated Regeneration” or DIR is a water softening process that is added to measure the water consumption over time, and to regenerate only when needed. This means that the water softener is given the trigger point to operate at a certain, customized time, based on the scheduled set. A DIR-abled water softener provides you with an advantage to prevent water wastage during the softening cycle. The system can do the thinking for you as long as you provide a default schedule in regenerating. 

Hard water can also contain other impurities such as iron, sediments, chlorine and chloramines that can affect the effectivity of the resin beads to wash away the hard minerals. In maintaining salt-based water softeners, it is recommended to have a periodic reconditioning of the resin tank in order to wash away the impurities or the contaminants. The frequency of cleaning still depends on the type of salt that the water softener is using, and the amount of calcium and magnesium ions that are collected from the hard water. Some components of the water softener are required to be replaced after some time, depending on the instructions of the manufacturer. Components such as the rubber asker, fittings and moving plastic parts are the usual parts that need to be refurbished for a longer lifespan of the softening unit.

Understanding Hard Water and Its Effects

Hard water is often prevalent at most households due to exposure of hard minerals. Adverse effects have been encountered with the usage of hard water. Limescale is a white, chalky or powdery substance that is usually found on the surface of faucets, shower filters, and water pipes. It is often a result of evaporated hard water that leaves off residue of undissolved minerals, and it is now evident among shower filters, faucets, water tube and plumbing fixtures. The process of forming limescale is called scale build-up, and several descaling agents are readily available in the market to prevent scale build-up. In order to avert the formation of limescale, reliable technologies have been devised as the water softeners. 
Water softeners are simple machines that have the sole purpose of providing soft water supply to the household. However, some water softeners are tailored with much more complex functionalities and operations in order to give the customer the full experience in the controls. 
Most people give advice that drinking hard water is not favorable because of the unnecessary minerals that come along with it. This is actually true, most especially when the water supply has a high level of hard minerals, the more exposed the body is to unpleasant side effects.

In terms of scale build-up, the following points are the primary negative effects caused by hard water:

  • Scale build-up shortens the full potential or the performance and lifespan of water-related appliances like hot water systems, dishwashers, and even washing machines.
  • The color of the clothes is starting to fade away and the clothes eventually become rough through constant usage of hard water in washing.
  • Soapsuds are difficult to achieve when using detergent or soap because hot water stops the formulating of bubbles. Soaps and detergents lose their effectiveness because the soap is combined with the hard minerals to form coagulated soap curd. The soap curd is sticky and insoluble that hangs around the clothes and clings to the skin. It can be troublesome when the soap curd sticks on to the hair. More soap is needed in order to form bubbles and continue with the washing. This can lead to wastage of soap that leads to unnecessary expenses. 
  • Soap residue is frequently seen among utensils and dishes because hard water is not capable to wash away soap effectively. 
  • The soap curd that is formed from soap and hard minerals can roughen the fabric that makes the clothes undesirable to wear.
  • Scale deposits are forming in the plumbing system, which can contribute a negative side effect towards the water pressure. Calcium and magnesium deposits reduce the flow of tap water in the pipe and through appliances. 
  • Insoluble soap deposits affects the actual washing procedures as it leave residue on anything that you wash. A slimy soap film is built up on the bathroom floor that is caused by dried soap deposits.
  • When the household is using a water heater, the hard minerals form limescale into the heating device, making it incapable of effective heating.

Hard water is the raw water that flux through the faucets, hoses, fountains, pipes and any other endpoint that the water goes through. It has not been filtered by any water filtering systems, as it is classified to be untouched. It is basically unprocessed water with high mineral contents, mainly calcium and magnesium.
When water travels underground, it picks up soluble substances along the way – a possible cause of contamination that makes the water unsuitable to drink, but it can be the simplest mean to acquire natural minerals that are mostly found in the earth. Calcium and magnesium are widely known hard minerals that stir limescale around the household, and that makes water supply hard. When water permeates through series of underground tunnels of rock and soil, it passes through coated minerals. 

Most households prefer to have soft water in their supply simply because soft water is safer to be drank and to be used for general purpose compared to hard water. The benefits of soft water are the following:

  • Smoother, softer skin due to the absence of hard minerals in the water supply.
  • No soap residues in dishes.
  • Improved water efficiency that leads to reduced energy bills.
  • No scale build-ups in the plumbing fixtures, showerheads, pipes and water-related appliances.
  • Extended lifespan on water-related appliances
  • Soap and detergent can lather up effectively. 
  • Clothes are softer and colors are no longer dimmed by the hard minerals. 

The Solution

Hard water cannot be prevented from forming because its source is from the underground facilities but it can be prevented from being drank and from being used around the household. Filtering the water by distillation and reverse osmosis are among the solutions to combat hard water. The use of water softeners and water descalers are also the solution. Some DIY packages are introduced for those who cannot afford to buy commercialized treatments – add powdered borax or sodium bicarbonate and filter the water through it.

Water filtration in faucets and water dispensers ameliorates the water’s taste and quality but its price tag can be quite difficult to take. Purchasing water softeners or filtering systems can be impractical as a household solution; however, its return-on-investment is worth the wait. You do not have to undergo major cleaning of pipes and plumbing fixtures, showerheads and faucet taps due to the scale build-up. Everyone in the household can drink potable water without the excessive hard mineral contents that the hard water provides. 


Reverse osmosis is the process of dissolving inorganic solids, such as sodium chloride or salt, and removing them from the solution, such as water. Reverse osmosis is executed when household water pressure pushes the tap water through a semipermeable membrane that is as thick as a cellophane. The membrane only allows water to flow through, preventing the contaminants or the impurities from passing through. The contaminants or impurities are collected outside the membrane and are flushed down the drain. The factors affecting the process of reverse osmosis are water temperature, water pressure, quality of the membranes and filters, and type and number of total dissolved solids in the tap water. 

Reverse osmosis is also used in desalinating seawater or the removal of salt from seawater. Hard water is pressured to pass through the fine membrane, forcing the minerals to be left behind outside the membrane. The only disadvantage of this method is that beneficial minerals are also filtered from the hard water.  


A magnetic-based system is also called as the anti-scale magnetic treatment. It operates by letting the hard water to pass through the magnetic field, reducing the effects of hard water. This type of system is not as large as a typical water softener because its components are very minimal, since it only uses magnetic force to convert hard water to soft water. It usually comprises of a display panel and a set of magnetic transmitters that are coiled around the water pipes. This treatment transmits water directly to the strong magnetic field. Two neodymium magnets are placed on both sides of the water supply pipe as water goes through, thus creating a magnetic force that lessens the effects of hard minerals to the pipes and appliances. 

This magnetic-based method is still scientifically controversial as published results are unavailable that can prove its effectivity in treating hard water. This method does not actually remove calcium and magnesium from hard water; it only decreases the effect of hard minerals towards the plumbing fixtures and appliances, and it makes limescale from forming to easily. Technically, the water is still hard as it passes through the magnets. 


A salt-based water softening system has an outstanding image of providing an effective way to soften hard water. It utilizes the process, ion exchange, in which hard water flows through a mineral tank that is comprised of polymer resin beads. A single polymer resin bead is charged with sodium ions. As hard water is flushed down the resin tank, the hard minerals, such as calcium and magnesium, are forcibly replaced with sodium ions, resulting to soft water. It also removes small amounts of dissolved iron. 

This type of filtrating system has a brine tank that utilizes to wash the hard minerals that are entrapped in the resin tank. The process of converting the hard minerals to sodium ion is known as regeneration. It uses an electronic metered valve that is mounted on top of the resin tank – this is employed to meter water by gallon, and to execute a cleaning cycle when the ion resin bed reaches a certain saturation level. During the cleaning cycle, the electronic valve circulates a series of back flushes to discharge the collected hard mineral particles. The sodium is needed to be replenished in the resin bed during the cycle. 

Salt-based water softeners are highly effective systems that can convert hard water to soft water; however, a concern has been raised about the high levels of sodium that the soft water contains after the ion exchange process. Soft water that is already processed with sodium ions is not best for drinking water. In other words, the soft water is not advisable for drinking purposes, most especially for people on sodium-restricted diet. Some salt-based water softeners back flush or regenerate once every two to three days. Generally, the regeneration cycle uses 10 to 20 pounds of salt, even more depending on the level of hardness in the water supply. 

If the hard water contains oxidized iron or iron bacteria, the ion exchange resin becomes coated or clogged with iron contaminants, and the water softener may not have an effective softening operation. In this rising dilemma, a method of removing iron that is called chlorination-filter or iron filter is necessary before hard water flows through the softener. Some water softening manufacturers have provided softeners that can accommodate iron filter, but it also comes with a price. 

Most of the salt-based water softeners are corrosive to the plumbing, especially when the softener is around five years of age upon usage. These softeners are not useful anymore to remove existing scale build-up in the pipes and on the water heaters.


A salt-free system operates differently from salt-based water softeners. Hard minerals are not actually converted or removed from the hard water; instead, their chemical form is changed and crystallized. These hard minerals are altered to hard crystal, resulting to the loss of binding or sticking properties to any surface. That means that the water still contains hard minerals but they can no longer cause scale build-up because the hard minerals do not have the binding properties that can adhere on any surface. 

The hard water is processed through a catalytic media called the Template Assisted Crystallization or TAC. In this process, the hard minerals are being transformed to hard crystal that is incapable to stick on anything. This is actually called water conditioning rather than water softening because the processed water is not considered soft. The water still incorporates hard minerals. 

An electrical valve is no longer needed because salt-free based system only works as a conditioner and never operates the capturing of hard minerals. 

Alternative Solution

Water descaling is an alternative solution to water softening. A typical water softener removes the problem, which is the hard minerals that are contained in the water, while a descaler addresses the damage created by the problem, which is the scale build-up. A salt-free water softener is actually a water descaler because it really never softens water. It only conditions the water to have inactive hard minerals. A magnetic-based water softener is sometimes considered a water descaler by some experts, but its effectivity in removing hard minerals still remains unproven scientifically.  

A water scale is the mineral components that is entrapped in the water, and adheres on the surface once water is evaporated. A water descaler system creates an electric charge in the water, holding the scale in the water and crystallizing it to prevent the scale from sticking on to any surfaces. 

A water descaler can be as beneficial as the water softening system, but it does not provide substantial, soft water. However, it is considered to be cheaper and economical compared to water softeners, especially in the installation and maintenance. Water descalers do not need much attention to maintenance, unlike to water softeners; maintenance and refilling of salt are among the religious repetitions that are needed to be done in water softeners. 

Salt-based water softening systems still require replenishment of salt that increases the chance of more expenses at home. Despite the expenses, you can still get the soft water you need at home. An extra caution is required when using salt-based water softeners as sodium is included in the soft water.

The disadvantage of a descaling system is that soft water is not its byproduct, but rather hard water with inactive hard minerals. You can be assured that the hard minerals are not going to form limescale in the plumbing fixtures, on faucets and showerheads, and to hinder normal household routines such as doing laundry and washing dishes. 

Salt Options

Choosing the type of water softening unit for your household is not enough. There are various concerns that need to be considered such as the expenses for the installation, maintenance and the prerequisite for the softening process to be fully working. 

Selecting a salt-based water softener is not only about deciding whether to employ salt in the process or not, but it also deems the type of salt that the softener needs. As opposed to a salt-free system, if you prefer to use a conventional water softener, then the choice of salt can have an impact to your expenses, to your health and to the environment. 

The types of salt that salt-based water softeners use are the solar salt, rock salt and the evaporated salt. Each water softener has its own salt requirement, depending on what model you choose. Essentially, taking time in reading the instructions manual is of the utmost importance. It is best to know the type of salt that your water softener needs to operate.


The solar salt comes from the evaporation of seawater, and it generally contains less insoluble substances compared to rock salt. Nevertheless, it also has more insoluble matter than the evaporated salt. Solar salt is leveled between the other two types of salt, and the level of buildups inside the resin tank is fair among the three. If the household consumes minimal water supply, then you may not notice its presence in the soft water.


The rock salt is not heavily processed, and it is the cheapest, the most economical salt. However, the rock salt has the tendency to have impurities that can cause buildups inside the water softener tank. This may cause you to conduct a regular cleaning routine of the tank.


The evaporated salt is more processed than the rock salt. This is used when the level of hardness in the water is way too high than the normal. It also has the strongest effect in eliminating hard minerals at a very large volume of water. This can also cause more buildups inside the tank.

Sodium VS Potassium Chloride

Sodium is the most common mineral that is utilized in most water softeners. Soft water usually contains sodium and it may not be the best for drinking purpose, especially when you are in a low-sodium diet. That is why manufacturers are able to come up with a water softening unit that can use potassium chloride, instead of sodium. Potassium chloride is not bad for your health, furthermore, it is also reckoned beneficial. It is environment-friendly compared to using sodium. The only problem is that potassium chloride is expensive, and it is not suitable for practicality. 


Most households use salt-based water softeners because they prefer to have soft water supply. These water softeners vary on the regeneration process, the control feature, and the volume of water that can be processed. Some water softeners are equipped with electric timers that trigger the flushing of excess brine solution and hard minerals, and the recharging of resin beads on a regular schedule. Other softeners are geared with computers that can calculate regeneration schedule of the resin beads based on the water consumption. The most common softeners utilize mechanical water meter to measure the water consumption, and boost the recharging process when sodium is already exhausted. Any approach comes its fair share of pros and cons. The electric timers are not able to dispense the soft water while recharging the resin beads. The computerized systems can only carry a reserved capacity of resin beads. The most flexible approach is the mechanical water softener that is geared with two mineral tanks – one tank contains the soft water, while the other refuels sodium.

No matter which water softening approach that you use, the most important aspect is that you are able to provide safe water for the whole household, may it be for drinking purposes, cleaning and household chores or for bath time. Numerous water softening units are available in the market, and your preferences matter on the type of unit you are going to choose. 

Related blogs