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Difference Between Salt-Based Water Softeners and Salt-Free Water Softeners 

What makes the one better than the other? Should you choose salt-based or salt-free water softeners for your house?  

Written by:
George Simms
Plumber & Contractor

Water softeners extend your household appliances’ lifespan and improve the texture of your hair and skin by reducing the harmful effects of excessive magnesium and calcium build-up in your water supply. These minerals can cause scaling in your pipework and leave a chalky white scum on your surfaces.

Other telltale signs that you may need a water softener include limescale buildup on coffee pots, your washing machine, silverware and glassware, faded or gray laundry, dry hair and skin, and a malfunctioning water heater.

To determine if you would benefit from a water-softener, have your water professionally tested or ask your municipality to provide the hardness classification for your water. Water is classified by milligrams per liter of dissolved calcium carbonate. 0-60 mg/L is classified as soft, 61-120 mg/L is moderately hard, 121 -180 mg/L is hard, and 180 mg/L or higher is very hard.   

If you notice hard water signs or your test results indicate you have hard water, using a water softener can help eliminate these issues. There are salt-based water softeners and salt-free water softeners.

"So what is the difference and which one should you buy?"

Why Do You Need a Water Softener?

Water known as hard water contains high calcium and magnesium levels that can adversely affect your pipework, household surfaces, appliances, and clothing.

Calcium and magnesium make it harder to work up a lather. This means you need to use more soap and shampoo when showering.

Excess calcium and magnesium ions can also affect your appliances, as scaling occurs when the minerals attach to your pipework. Because the water flow reduces due to the blockage, appliances such as dishwashers and washing machines need to work harder. This results in higher energy bills and more wear-and-tear on the components. 

When you use hard water to wash laundry, you could find your clothing quickly fades and feels rough. This can lead to spending more money on new clothes earlier than necessary.

While The Environmental Protection Agency (EPA) regulates how many minerals and chemicals should be in the public water supply without posing a health risk, many consumers still have concerns about their water quality. Staying hydrated is essential to human health, and it’s vital to have access to a clean drinking water supply. Although tap water is generally safe in most areas, anyone who wants to remove even more minerals and chemicals from their drinking water can benefit from a water softener.

Salt-Based Water Softeners

Salt-based water softeners use a process called ionization to transform hard water into soft water. As magnesium and calcium ions flow through your pipework, a salt-based water softener replaces these harmful minerals with a less damaging alternative. 

A salt-based water softener uses a porous plastic resin covered with positive sodium ions. When the hard water passes through the resin, naturally occurring calcium and magnesium ions attach to the surface, simultaneously releasing positive sodium ions into the water. This process maintains an electrical charge balance on the resin.

As more hard water travels through the resin and becomes soft water through the ion exchange process, the resin eventually has an excess supply of calcium and magnesium ions and a reduced number of sodium ions. The intelligent water softening unit performs a regeneration process to remain effective. 

By rinsing the resin with salt water, the enormous number of sodium ions in the salt displaces the calcium and magnesium ions which flush down the drain. This process often happens when water is least likely to be in use, such as overnight, ensuring your system is ready to supply softened water for the next day.

The amount of sodium released by a salt-based water softener is relatively low and should not cause harm. However, if you have concerns about your sodium intake, you can purchase resins that release potassium, and these use the same process to replace the calcium and magnesium ions. You can also buy a salt-free water softener.

Salt-Free Water Softeners

A salt-free water softener uses an alternative filtration system to reduce the adverse effects of magnesium and calcium. Rather than replacing calcium and magnesium ions, salt-free water softeners alter their physical structure. This process ensures the minerals can not attach to your pipework and eliminate the scaly limescale build-up you may notice on your dishware. 

Known as template assisted crystallization (TAC), salt-free water softeners utilize a surface material called media. The media contains many polymer beads which are covered with tiny craters. When hard water flows through the media, the recesses trap the calcium and magnesium ions and hold them in place. As the craters attract more ions, the magnesium and calcium form microcrystals.

"When they are large enough, these micro-crystals break away from the craters and travel through the water supply "

However, these structures do not change shape or size as they flow through your plumbing system. This stability ensures the microcrystals do not attach to your piping, preventing limescale.

Which System Should You Buy?

Both types of water softeners can reduce magnesium and calcium levels in your water supply, and your choice comes down to personal preference. Some consumers prefer to install a salt-free water softener because you don’t need to keep a salt supply to keep the unit in operational condition. 

Salt-free systems can be cheaper, and they don’t need much maintenance. It can be expensive to replace pipework with damage from scaling, and a salt-free system prevents this source of harm.

However, many advocates of salt-based water softeners point out that a salt-free system does not remove calcium and magnesium from your water supply. Technically, a salt-free water softener is more of a water conditioner. Although the micro-crystals can’t attach to your pipework, they remain present in the water.

This method can mean you still end up with a chalky residue on some surfaces, and your clothing may fade after washing. You can consider how much these stains bother you and how hard they are to clean from your surfaces before deciding which type of water softener is best for your needs.

It’s also essential to think if you want to spend time adding salt to a salt-based water softener and if you are happy with the extra expense over an extended period. Deciding which system offers better value for money, combined with performance, depends on how hard your water is and what kind of effect it has on your home.

About the Author

George Simms is a Salt Lake City based plumber and contractor, with a focus on aiding homes and businesses (particularly farm) solve problems with hard and contaminated water. Walter is here to share his wealth of job experience and a knowledge of both modern and antique plumbing.

Last Updated on December 9, 2021