How Does a Water Softener System Work

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You’ve probably heard that hard water is bad for you and your home, but you’re not sure why. Hard water can cause a lot of problems for both your home and your health. The minerals in hard water can clog pipes and make it difficult to get soap suds to form when you shower. This makes it tough to get clean and even leads to skin irritation.

A water softener is an important element at home because it prevents these problems from happening. A water softener works by exchanging the hard minerals in the water with softer ones, like sodium or potassium. This keeps your pipes clear and helps your skin stay healthy and itch-free. Here's everything you need to know about the working of a water softener.

What is a Water Softener?

A water softener is a whole house water filter system that removes hardness causing calcium and magnesium minerals from your home through ion exchange. These mineral deposits can cause hard water. If you have ever seen a mineral deposit on your shower head or faucet, you have probably experienced the effects of hard water.

What is a Water Softener?
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When water flows through a water softener, the system filters these hard water minerals, and the softened water then leaves the water softening system to flow through plumbing.

Ion exchange is when the calcium and magnesium ions in the water are exchanged for sodium or potassium ions. This process helps prevent the buildup of mineral deposits in your home and keeps your water soft and clean.

What is Hard Water?

This is household water that contains a high concentration of dissolved minerals, specifically calcium and magnesium. These minerals aren’t toxic and don’t make water unhealthy to drink, but they can be harmful just the same. Hard water wreaks havoc on the modern home.

What is Hard Water?
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Hard water causes cloudy water spots on sinks, dishes, silverware, bathtubs, and showerheads. Some people also report feeling itchy on their skin after bathing or showering in water that is very high in mineral content. And because shampooing doesn’t lather up very well in hard water, shampooing leaves you with dull hair that’s difficult to style.

Hard water can also be destructive when you consider the harmful effect it has on your plumbing systems, fixtures, and appliances. As water runs through the supply pipes and then out of faucets, your showerhead, ice maker, washing machine, water heater, boiler, and dishwasher, the minerals in hard water stick to the insides of these pipes and appliances, slowly but surely building up over time.

Mineral scale buildup in faucets or water heaters may shorten their lifespan. This scale not only clogs your pipes but also reduces the efficiency of your appliances and shortens their lifespan. In extreme cases, hard water deposits can dramatically restrict the water flow in your home, putting undue pressure on the whole plumbing system. However, investing in the best water softening shower head can help you soften your water.

Types of Water Softeners

Ion Exchange

Ion Exchange
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This is the most common type of water softener in-home application. It works by removing calcium and magnesium ions and replacing them with sodium ions, which have none of the damaging effects of calcium and magnesium. This is a familiar device that includes a large tank of salt pellets.


Salt-free uses a mechanical filter to remove calcium but doesn’t work very well on very hard water. It doesn’t remove magnesium.

Reverse Osmosis

This device filters water through a semipermeable membrane that removes as much as 98% of water impurities. It’s a bit of an expensive appliance, and it uses a considerable amount of water. It’s also very good at removing other impurities, calcium, and magnesium.

However, the use of reverse osmosis for drinking water can have negative effects. The human body needs minerals derived from drinking water, among other sources. Long-term use of reverse osmosis can have unintended consequences and deplete the human body with important minerals.

How a Water Softener Works

How a Water Softener Works
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Your Water Softener is Installed

The first step of softened water is to have the water softener installed. Leave this to professional plumbers because they know how to install the water softener shower head without interfering with your home plumbing system. They’ll also need to find a good drainage spot so the unit can properly do its job.

The water softener can be installed in the basement, garage, utility closet, or wherever water enters the house. A typical water softener consists of a tall, narrow water softener tank and a short, wide brine tank. The softener tank is connected to your home’s water supply line.

A small diameter fill tube connects the brine tank to the softener tank. And a discharge hose runs from the softener tank to a nearby drain pipe or drywell. The softener tank is filled with formulated resin beads, which are permanently sealed inside the tank. The brine tank has a removable lid so you can fit in with salt pellets or potassium chloride pellets.

Microscopic Beads Trap Hard Water Minerals

Inside the softener tank, there’s a bed of tiny resin beads. These beads are specially formulated to have a strong negative charge, while calcium and magnesium carry positive charges in water. The beads attract and trap charged particles of hardness minerals floating in the water.

As water flows through the softener tank, the hardness minerals attach themselves to the beads. This process is called ion exchange. Eventually, all the beads in the tank will be coated with hardness minerals.

The Brine Tank Flushes Away Hardness Minerals

The softener needs to be recharged or regenerated when the beads are coated with hardness minerals. People often ask how long does it take for a water softener to regenerate or how to manually regenerate water softener?

A concentrated salt brine solution is flushed through the resin beads during regeneration. The high concentration of salt breaks the bond between the hardness minerals and the beads.

The brine tank is filled with salt. But problems may result if you’re on a restricted low sodium diet since a small amount is transmitted into the drinking water during the regeneration process. Sodium can also affect the bacteria in septic systems that are necessary for the breakdown of waste.

The hard water minerals are flushed down the drain, and the beads are ready to soften more water. Depending on the size of your softener and your water hardness, a typical regeneration cycle can last anywhere from 30 minutes to two hours.

Your Water Softener Regenerates

The regeneration process uses sodium to detach the mineral buildup from the resin. Sodium has a charge strong enough to take the calcium and magnesium away but not enough to cling to the resin itself. The regeneration process consists of three cycles. These include:


Regeneration starts with a backwash cycle in which the valve reverses the water flow in the tank and flushes the tank of debris. This debris is then eliminated through the drain connected to the municipal sewer system or septic system.


In the recharge cycle, a salty solution is pumped from the brine tank into the mineral tank. The highly concentrated salt solution forces the magnesium and calcium off the beads, and the mineral rich, salty water is flushed out of the tank and down the drain.


In the final rinse cycle, fresh water is used to rinse the beads clean of any residual salt. The regeneration process is halted, and the water softening process repeats itself. In the freshly regenerated mineral tank, the beads are coated with sodium or potassium provided by the brine tank.

As additional hard water enters the mineral tank, the positively charged calcium and magnesium in the water are attracted to the plastic beads, replacing the sodium on the beads. This small amount of salt displaced from the beads becomes suspended in the water and moves on into the home water supply.

This amount of salt in water is not a problem unless you have strict limitations on sodium. When the beads again become saturated with hard water calcium and magnesium, the control valve starts a new regeneration cycle and flushes the hard water minerals down the drain once more. This ongoing cycle continues as long as the brine tank is kept stocked with salt or potassium pellets.

The Dual Cylinder Regeneration Process

A dual cylinder softener cleans and regenerates both sides of the resin bed at the same time. This design is considered more efficient than a single cylinder system because it doesn’t have to shut down completely during the regeneration process. Each side of the resin bed is cleaned in turn while the other side continues to soften water.

Single cylinder water softeners need to pause the water softening process to regenerate, while the twin cylinder design means that the regeneration process can take place at any time without interrupting your enjoyment of softened water.

Components of a Water Softener

A water softener is made up of three components, including a control valve, a mineral tank, and a brine tank. These three components work in conjunction to remove the minerals from hard water, monitor the flow of water, and periodically clean the system through a regeneration process:

The Mineral Tank

This is the chamber where water softening happens. The water supply line feeds the hard water into the tank. The water seeps through the bed of resin beads, depositing the water and hardening calcium and magnesium ions. The water exits the tank soft and flows through your pipes and out to your household appliances.

The Control Valve

The control valve is the brain of the water softener. It monitors the amount of water flowing into your home, keeping track of how much hardness is being removed from the water. When it’s time for regeneration, the control valve initiates the process.

As the hard water flows through the mineral tank, the resin beads exchange their sodium ions for hardness ions. Over time, this depletes the capacity of the resin to continue to effectively soften water. The control valve automatically initiates a regeneration process before the beads become too burdened with mineral content to continue removing calcium and magnesium ions.

The Brine Tank

The brine tank stores a highly concentrated solution of salt to restore the resin beads’ positive charge. Salt is manually added to the brine tank in the form of pellets or blocks. This dissolve in the water at the bottom of the tank.

When the control valve registers, the softening capacity of the resin diminishes, and the heavy brine solution is drawn out of the tank and flushed through the resin in the mineral tank. If the brine tank runs out of salt, the water passing through the unit will no longer be softened.

FAQs on How a Water Softener Works

How does a water softener work?

A water softener works by exchanging the hardness ions in your water with sodium ions. This is done using a process called ion exchange. Ion exchange is when one substance exchanges place with another substance of a similar size and charge. In this case, the calcium and magnesium hardness ions exchange places with sodium ions.

What is a two part water softener?

A two-part water softener is a type of water softener that uses two tanks. The first tank is the mineral tank and contains the ion exchange resin. The second tank is the brine tank and contains salt (sodium chloride). As water passes through the mineral tank, the hardness ions are exchanged with sodium ions.

The brine tank is used to regenerate the resin. During regeneration, salt water is pumped from the brine tank and into the mineral tank. This flushes the calcium and magnesium hardness ions from the resin and replaces them with sodium ions. The regeneration process takes about 1-2 hours.

What are the benefits of a water softener?

Water softeners can provide many benefits, including:

  •       Reduced soap consumption – Since soap works more efficiently in soft water, you can use less soap to get the same results.
  •       Longer-lasting clothes – Hard water can cause clothing to wear out more quickly. Soft water can help your clothes last longer.
  •       Reduced energy consumption – Hard water requires more energy to heat. As a result, softened water can save you money on your energy bills.
  •       Improved plumbing – Hard water can damage your pipes and fixtures. Softened water can help prolong the life of your plumbing.

Final Thought on How a Water Softener Works

Water softeners are an important part of keeping your home running smoothly. By understanding how they work, you can be sure to get the most out of your investment. Also, make sure your system is annually checked by the contractor who installed it to ensure it is working properly.



Kristina Perrin

Kristina Perrin

Kristina is an expert DIY home remodeler and mom to three. When she's not cooking or experimenting with new recipes, you can find her working on new home improvement projects or writing about her favorite kitchen appliances or DIY projects on Kitchen Infinity blog.

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