Water Softener Salt: Importance of Salt to Water Softeners

Water Softener Salt Everything You Need to Know

If you’re like most people, you probably don’t think about water softener salt all that often. But if you have a softener, it’s an essential part of softening your water.

In this guide, we’ll discuss the various forms of salt available and how the type and quality you use can affect the softness of your water and how often you must perform maintenance. We explain the difference between standard salt and potassium chloride to help you decide which one is better for you. We also provide tips for maintaining your softener and show you how to add salt to your tank.

So, whether you’re a first-time homeowner or a seasoned pro, read on for all the information you need about water softener salt!

Water Softener Regeneration and Salt

Water softeners use a process called ion exchange to soften water. In this process, hard water minerals such as calcium and magnesium are exchanged for softer ions like sodium or potassium. This is done in a tank filled with resin beads, which attract the hard water minerals.

Regeneration process

water softener salt crystals
Salt is used to regenerate the ion exchange resin in most water softeners.

As the resin treats water, it gradually becomes saturated with calcium and magnesium ions. Eventually it will reach a point where it can’t remove any more minerals, so the softener will need to be regenerated. This is done by flushing the resin with a salt solution, which removes the calcium and magnesium ions and replaces them with sodium or potassium ions.

These “cleaning” ions come from salt. Most people use conventional salt, which in chemistry is known as sodium chloride. Some people prefer potassium chloride. Both salts work equally well.

If you use conventional salt, the media is regenerated by sodium ions. If you use potassium chloride instead, then potassium ions will regenerate the resin.

The frequency of regeneration (or how often your softener needs to run) depends on your water hardness, the volume of water you use each day, and the amount of resin your system has.

On average, a water softener will need to be regenerated every 1 to 3 weeks.

Regeneration equipment

Every water softener includes the equipment and controls necessary to regenerate the resin. This includes:

  1. brine tank: this is a tank that stores you salt, usually as a slurry or brine solution
  2. control valve: the water softener has automatic valves that take the resin tank out of surface and flush it with salt water. Once the resin is regenerated, it is flushed with clean water to remove the salt.
  3. timer or flow control system: water softeners use either a timer or a flow monitor to determine when it’s time to regenerate the resin.

Sodium Chloride versus Potassium Chloride

All ion exchange water softeners must be regenerated when the resin becomes saturated. This is done by flushing the spent resin with a brine solution containing either sodium or potassium ions. These ions replace the hardness (calcium and magnesium ions_ that has been removed from the resin.

You can use either conventional salt – sodium chloride, or potassium chloride. Each one of these works just as well in the regeneration process. Either option can reduce your water hardness.

What is sodium chloride

Table Salt and Shaker
Sodium chloride (table salt) is the most common salt used to regenerate residential water softeners.

Sodium chloride is known as “table salt” or “rock salt.” It is a mineral made of sodium and chlorine atoms, and it is found in many forms including rock, brine, and sea water.

Sodium chloride is the most common type of salt used in water softeners. It offers several advantages.

  • inexpensive
  • readily available and easy to find
  • many brands to choose from
  • works well in softening water
  • available in various forms (pellets, rock, solar salt)

Limitations and disadvantages of using sodium chloride to regenerate your water softener include:

  • adds sodium to the softened water
  • salt is discharged to the environment

What is potassium chloride

Potassium chloride is also a salt. It is made of potassium and chlorine atoms. It is found in nature, but it can also be manufactured synthetically. Read my article on using potassium chloride in water softeners.

Potassium chloride offers advantages of conventional salt.

  • does not add sodium to treated water
  • high purity
  • environmentally friendly – no sodium or chloride added to groundwater or rivers

However, potassium chloride has disadvantages compared to conventional salt for your water softener.

  • expensive (4 – 8 times higher than salt)
  • can be difficult to find

Concern over sodium in drinking water

Using regular salt in your water softener adds a small amount of sodium to the treated water. For people who restrict their sodium intake, this may be a concern. Potassium chloride does not add sodium to softened water and is a key reason many people use it in place of conventional salt.

Water that is softened with sodium chloride has about 12.5 milligrams (mg) of sodium in an 8-ounce glass. If you drink 8 glasses of water a day like me, then you’re getting 100 mg of sodium from your softened drinking water.

The CDC recommends a limit of 2,300 mg of sodium per day as part of a healthy diet. If you are concerned about sodium, then talk to your doctor. You can use potassium chloride to effectively regenerate your water softener and eliminate sodium if you want to.

Learn all about salt free water softening in my comprehensive article.

Is one better than the other

The choice between using sodium chloride or potassium chloride is mainly a matter of personal preference. Both salts work equally well in the regeneration process.

Some people prefer potassium chloride because it does not add sodium to the water. They also like the fact that it is more environmentally friendly – it doesn’t add sodium to groundwater or rivers and streams like regular salt. However, it is more expensive and harder to find than sodium chloride.

Conventional salt – sodium chloride, is less expensive and easier to find than potassium chloride. It works just as well in softening water. Some people don’t like regular salt because it adds sodium to the softened water.

It is important to note that both salts work equally well in regenerating ion exchange resin and removing hardness from water. The choice is yours

Forms of Salt for Water Softeners

The salt you add to your water softener comes in many forms. What do we mean by form?

The form of salt is the physical shape and size of the salt. The most common forms are:

  1. Block salt
  2. Crystals
  3. Evaporated pellets
  4. Rock salt
  5. Solar salt

Some forms of salt are purer than others, and impure water softener salt can leave behind a non-soluble residue in your backflush tank. These deposits require manual removal and can foul your water softener. However, pure salt varieties are generally more costly.

The following table summarizes the five types of water softener salt, their purity, and properties that make them unique.

Salt TypePurityDescription
Block SaltLowUnless the owner’s manual explicitly states otherwise, avoid using salt block in your water softener. Block salt contains a lot of impurities that can hinder the regeneration of your resin or cause a malfunction.
Crystal SaltVariesSalt crystals are the most commonly used type of water softener salt. It is readily available, works well, and is the least expensive.
Evaporated Pellets99.99%Plumbers opt for evaporated salt as their go-to solution to soften water because it is the purest form of salt and is remarkably effective at treating hard water problems. This salt provides the most efficient resin regeneration of all 5 types.
Rock Salt87 – 99%Rock salt is one of the more popular options, but it contains many impurities such as calcium sulfate. Its low purity may require frequent maintenance. On the flip side, it is very cost-effective.
Solar Salt99.60%Solar salt is naturally-created when the sun evaporates seawater, thus earning its name. Its exceptional purity and solubility make it ideal for systems prone to salt bridging or mushing.


Block salt

Block salt is exactly what it sounds like. It’s a solid block of salt. This type of salt is available in very high purities which makes it desirable.

However, most water softeners can’t use this form of salt because it dissolves at a different rate than other forms and may not fit in the brine tank.

Some filters, though, are designed to work with block salt. Consult your owner’s manual to see if your filter can use this form of salt.

Read my comprehensive article on block salt for water softeners.

Salt crystals

Salt crystals are small, granular pieces of salt. This is the most common form of salt used in water softeners. It is easy to find and comes in a variety of brands.

Salt pellets

Salt pellets, also known as evaporated softener pellets, are manufactured to be uniform in size and shape. This type of salt prevents common salt problems like bridging and accumulation along the walls of the brine tank.

Check out my article on salt pellets for water softeners.

As the name suggests, evaporated pellets are made by evaporating salt water. This process produces a very high purity in the final product. Evaporated pellets are the purest form of salt you can purchase. Most brands are available in 99.9% purity. Impurities can result in scaling and deposits in your water softener and can clog valves and piping.

Pellets are the most expensive form of salt you can use in your water softener. This is because of the extra process required to purify the salt and extrude it into pellets. Many people feel this type of salt is worth the added cost because of its purity and reduced fouling problems.

Rock salt

Rock salt is obtained from natural mineral deposits call halite. This is the least pure of all salts that can be used in water softeners. It is also the lowest cost option available – which is why many people elect to use it.

Rock salt contains high concentrations of calcium sulfate – this impurity is not soluble in water and causes bridging and blockages in your water softener.

If your softener is an “all-in-one” system, you shouldn’t use rock salt. Some water softeners are designed to work with this lower cost salt – they are known as “two-part” systems.

Solar salt

Solar salt is made by evaporating brine in large solar heated ponds. It is mainly sold as softener crystals, but some brands sell it in pellet form. Pellets are less likely to clog your system, but also cost more.

This type of salt has a relatively high purity, ranging up to 99.6%. It is less expensive than evaporated pellets, but more costly than rock salt. This makes it a great mid-range price point for homeowners.

Factors to Consider When Choosing Softener Salt

When you look to purchase salt for your water softener, there are a lot of variables to consider. It’s important to remember that not all salts are the same. It can seem overwhelming, but we’re here to help.

Salt purity

Impurities in softener salt can cause problems in your system. Bridging and blockages are two of the most common. Most salts available for water softeners have at least some impurities.

The higher the purity of a salt, the less likely it is to cause problems in your system. Evaporated pellets and solar salt are two of the purest forms available, with purities up to 99.99%. These are also the most expensive forms of salt.


Morton Clean and Protect PelletsDiamond Crystal Pellets
There are more than a dozen brands of salt available for water softeners. Not all are created equal – some have higher purities than others. Some manufacturers offer salt in various forms (rock salt, pellets, solar) and offer both conventional salt and potassium chloride.

The following companies make salt for residential water softeners.

  • Advantage Salt Supply
  • Cargill
  • Compass Minerals
  • Diamond Crystal
  • Dura-Cube
  • Kissner
  • Morton Salt
  • Nature’s Dream
  • Tier 1
  • Tru-Soft
  • Water2Buy
  • Windsor Salt


The cost of salt varies widely, depending on the purity and brand. Crystals are the most common form of salt and are generally less expensive than other forms. Evaporated pellets are more expensive than crystals, but they offer very high purity and convenience.

If you want to know the cost to install and operate a water softener, check out my article.

Salt Usage

Beside the cost to purchase and install your water softener, salt is the most significant cost for homeowners. How much salt you use will depend on how much water is treated, the hardness of your water, and the settings on your regeneration cycle.

Water hardness vs salt requirement

Water softeners remove calcium and magnesium from your water. The higher the levels of these minerals in your water, the more frequently the resin must be regenerated.

When the resin is spent, it must be flushed with a high concentration of salt to remove the minerals. The salt provides ions that displace the calcium and magnesium that are adhered to the resin. Depending on the type of salt you use, this is done by sodium ions (conventional salt) or potassium ions (potassium chloride).

The harder your water, the more softener salt you will need in order to regenerate the resin bed.


Water softeners use ion exchange resins to remove hardness from the water. The resin has a specific capacity of hardness it can remove, expressed in grain capacity. This capacity is directly related to how much resin your system has.

Another important factor in your water system’s capacity is the amount of salt used to regenerate the resin.

The amount of treatment that your water softener can provide depends on the amount of salt that was used to regenerate the resin. Let’s look at how much softening 1 cubic foot of resin can provide with different amounts of salt used to regenerate it.

Amount of Salt Used in Regeneration

Water Softening Capacity

6 lbs

20,000 grains

9 lbs

25,000 grains

18 lbs

32,000 grains

Other considerations availability, shelf-life, quality of brand, and the type of bag the salt is sold in. I always check reviews before buying anything, especially something as important as my water softener’s salt.

Adjusting the regeneration cycle on water softeners

It’s important to set the regeneration cycle on your water softener to minimize the use of salt and water.

This process begins in the design phase when you select the size of softener. It should be sized so that it does not regenerate more than every 3 days, nor go longer than 14. If your unit cycles every 3 days, you’re using more salt and wasting water. If it happens every 2 weeks, the resin can become compacted from being in service for so long and the salt can form cakes and bridge. The optimum regeneration time frame of 7 days is best for most situations.

Read my complete guide to properly sizing a water softener.

Maintenance Tips

Your water softener needs a little TLC every now and then to keep it running at peak performance.

Here are some simple tips to help you out:

  • Check the salt level in your brine tank regularly and refill as needed. A low salt level can cause the water softener to not regenerate properly and allow hard water to enter your plumbing.
  • Clear any scale or crust that may have built up in your brine tank. This can interfere with the proper operation of the water softener.
  • Drain and clean your brine tank once a year. Remove all sediment and scale from the tank and discharge piping and other accessories.
  • Sanitize your system at least once a year. This will prevent harmful bacteria from growing in your water softener and plumbing.
  • Test the removal efficiency of your system annually. Replace the resin bed every 5 years to keep your system running at peak performance.

Read my article 10 Tips for Maintaining Your Water Softener to learn more about keeping your unit in top shape.

Purity and scaling

The purity of water softener salts has an effect on the amount of maintenance your water softener will require.

Salt with a low purity can result in deposits forming on the brine tank and the automatic valve manifold. If severe enough, these deposits can cause the water softener to not function properly.

If you use rock salt, which comes from mines and natural deposits, you may find that the higher amount of impurities and insoluble minerals will result in sediment and other solids depositing in the bottom of the tank. This material can interfere with the proper operation of your water softener.

Salt with a higher purity, such as solar or evaporated salt, doesn’t contain the high level of impurities that rock salt does. This makes it a better choice for use in water softeners.

Using a softener salt with a higher purity will help reduce the amount of maintenance required and keep your system running smoothly.


Salt in your tank can form bridges after it sits for a while. This happens when the salt becomes packed together and forms a solid mass or clumps. The bridge prevents water from flowing evenly through the tank which can reduce the salt concentration of the regeneration rinse. This reduces the amount of hardness that is removed from the water and can cause problems in your home’s plumbing system.

If you have a bridge in your tank, it will be noticeable because the salt level will be much higher on one side of the tank than the other. You may also see an accumulation of sediment on one side of the tank. If you do notice these signs, break up the bridge by stirring the salt with a long stick or shovel.

Salt can also form cakes and clumps over time. This happens when the salt becomes wet and mixes with the water in the tank. The cakes and clumps will eventually harden, which will prevent water from flowing through the tank properly.

The best way to prevent bridging is by keeping the softener salt level in your tank high enough so that it doesn’t have a chance to form a bridge. Keep your tank at least 25% full to avoid these problems.


Iron is a common element that can be found in water. It can cause problems in your plumbing system and may also discolor your clothes.

Despite the fact that water softeners remove hardness from water, they don’t work very well with iron. Iron can cause problems in your water softener such as scaling or accumulated of precipitated iron solids. This can interfere with the proper operation of the automatic regeneration valves or foul the piping components of your softener.

You can use special cleaning agents to remove iron from your water softener. It is recommended that you remove the iron from your system once a year with one of these products.

Sanitizing and cleaning

Your water softener can become contaminated with bacteria or viruses if it isn’t properly sanitized and cleaned. This can cause health problems for you and your family.

Another common problem is the growth of sulfate reducing bacteria in the salt tank or resin vessel. These bacteria produce hydrogen sulfide which creates a rotten egg smell in your water.

To prevent this from happening, it is important to sanitize and clean your water softener at least once a year. You can do this by using a commercial sanitizer or a bleach solution. Be sure to follow the manufacturer’s instructions carefully.

Adding Softener Salt to Your Water Conditioner

Salt is the primary long-term cost and maintenance item for your water softener. You don’t have to replace the salt – you just keep adding it as necessary. Your salt usage will vary by the amount of water you use and the hardness of your water.

Here are some good rules of thumb for adding salt to your water conditioner to maintain optimal performance.

  1. Add salt to your tank when the water level is above the top of the salt.
  2. Keep your tank at least 1/4 full at all times.
  3. Fill your tank to no more than 4 inches from the top.
  4. Break up any clumps or bridging when you notice it.


How long should a 40-pound bag of softener salt last in my water softener?

In general, a 40-pound bag of salt will last one month in a water softener. If you use a lot of water or have very hard water, then you’ll use more salt. If your water is relatively soft or you don’t use much, then the 40-pound bag might last as long as 2 months.

Which softener salt is best for water softening?

You can use any salt that is sold as water softening salt in your system. Salts with a high purity, such as evaporated pellet salt, works very well. Rock salt, which is the cheapest, has a lot of impurities that cause maintenance issues – although it still works fine for regenerating your water softener.

How often do you need to add salt to a water softener?

Add salt to your brine tank when the tank is less than half full. If the salt looks wet or is below the water level, add more salt.

Does it matter what type of salt I use in water softener?

You can use any salt that is labelled as water conditioner salt. This includes solar salt, rock salt, pellet salt, and potassium chloride. They all work well and can be used to regenerate your softener.

Are salt delivery services worth the cost?

Many people have their softener salt delivered to their house. Is delivery worth the cost? It depends. If you struggle to lift heavy bags of salt, don’t want to shop at the big box stores, or forget to keep a supply on hand, then delivery is for you. Simply sign up for an account with a local company and you’re all set.


Whether you’re just starting with a new water softener or need to know how to replace your salt, we hope this guide has been helpful.

Which type of salt should you use? How much do you need per regeneration cycle? What are the maintenance tips for your softener, and how can it help with hard water issues in your home?

Maintaining your water softener can be overwhelming if you don’t understand how it works. We hope this article demystified the process and gave you a better understanding of water softener salt.

Boch Richard

Richard Boch is a chemical engineer responsible for designing water filtration systems for industrial and residential customers. He has more than 20 years of experience with ion exchange, activated carbon, and reverse osmosis. Richard's expertise has made him a go-to source for municipalities and businesses looking to improve their water quality. When he's not working, Richard enjoys spending time with his wife and two young children.

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