Water Softener: How Does it Work, Advantages and Disadvantages of Using a Water Softener

A water softener is typically a filtering agent or appliance meant to remove magnesium and calcium in the water. What most people do not know is that all water is not the same, especially regarding its chemical composition. Some water has high amounts of magnesium and calcium minerals absorbed from the earth, making it hard. If the water lacks such minerals or has them in limited quantities, it is regarded as soft. Water from streams and lakes are naturally soft.

However, underground water in regions with high amounts of chalk, gypsum, and limestone, tend to be hard. Therefore, to make the water soft, a water softener is used to remove the mineral components that make it hard. Water softening is thus the process of removing the calcium and magnesium, among other metal cations in the water.

Here is more on water softening, why it should be used, how it works, and some of the advantages and disadvantages of water softening.

Types of Water Softeners

Water softening, as earlier mentioned, employs a filtration device, system, or appliance to remove the calcium and magnesium in hard water, making it soft. There are three general types of water softeners including:

1. Ion exchange

It is the most common type of water softener and is well known for its domestic use. It replaces the metal ions of calcium and magnesium with sodium ions. Sodium ions do not possess the damaging effects that arise from using water filled with calcium or magnesium ions.

For the device to work, a large tank is filled with salt pellets and then comes in the hard water. The sodium ions in the salt will react and replace the calcium or magnesium ions in the water, making it soft.

2. Salt-free

It is a device which possesses several shortcomings as it uses a mechanical filter to remove calcium. It is ineffective with water that has magnesium as it cannot remove the metal element. It, therefore, does not work particularly well with hard water. In other words, it is generally purposed for removing calcium from hard water.

3. Reverse osmosis

The device allows water to pass through a semipermeable membrane which removes about 98% of impurities. It uses a considerable amount of water and is pretty expensive. However, it is very good at removing chemical impurities such as magnesium, calcium, and others.

How Do Water Softener Works?

For this description, we will refer to the ion exchange type of water softener as it is the most commonly used. In the process, calcium and magnesium ions in the water are eliminated and replaced with sodium ions. Once hard water enters a mineral water tank, it flows through a bed of spherical resin beads. The beads are made from polystyrene and are charged with sodium ions. Since the beads are anions, they have a negative charge. The calcium and magnesium ions have a positive charge making them cations.

As opposite charges attract, the magnesium and calcium charges will be attracted to the negative charges on the resin beads. The beads continue to grab the mineral ions, displacing the sodium charge that once was on the beads. The end product is water that is void of calcium and magnesium charges. The resin beads continue to strip the hardness out of the water in the mineral tank with soft water entering your home.

Eventually, the beads become too burdened with mineral content and might fail to effectively remove the calcium and magnesium ions. As such, the control valve in the water tank initiates a regeneration cycle. The control valves allow water softening units to be extremely efficient. The maximum capacity is pre-programmed on the control valve’s onboard computer, depending on the size of the house, the number of occupants and the level of hardness of the water.

A brine tank is also added to help the system in regeneration. It holds a highly concentrated solution of salt, containing either sodium or potassium which restores the positive charges on the resin beads. As it sits adjacent to the mineral tank, the salt is manually added to the brine tank as pellets or blocks which dissolve in the water.

The control valve’s computer will at a one-time signal that the softening capacity of the resin is diminishing. At such a time, the heavy brine solution will be drawn from the tank and will be flushed through the resin in the mineral tank. In the event the brine tank runs out of salt, the water will not be softened.

Why Should You Use a Water Softener?

1. Basically, it softens water!

Water softeners remove the calcium and magnesium ions that make water hard, making it soft and relatively safe for use and consumption.

2. It improves the mineral content balance of the water

Water softeners replace the calcium and magnesium ions with sodium. Also by significantly reducing the levels of calcium and magnesium in the water, it lowers their concentration at the optimum levels that may benefit one’s health instead of causing harm.

Besides, when sodium is used in water softening, it balances other minerals in water and comes with the advantage of added sodium in optimal quantity, which is actually recommended for daily intake. Healthwise, sodium aids in controlling the body’s fluid balance and sending nerve impulses.

3. Removes toxins such as ferrous iron

Water softeners, apart from removing the ions that make water hard, also removes small quantities of ferrous iron or dissolved iron, which exists in a soluble state. The iron is responsible for darkening the color of the water as well as leaving visible stains on the toilet, bathtubs and other sinks.

4. Lowers costs of appliance repairs and unnecessary replacements

Hard water is responsible for endless appliance repair bills and scale-ridden pipes. Using a water softener will preserve those pipes and end the frequent calls to the repairman. It will also save your sinks, bathtubs, and toilets from the annoying stains.

5. Makes laundry and general cleaning easier

Hard water is responsible for stiff laundry and dry hair as it reduces the capacity of water to react with soap. For this reason, using it makes it tough to wash the hair properly. It also makes it difficult to straighten laundry and washing in general due to its effect of reducing the capacity of soap to react. A water softener will eliminate all this trouble.

Advantages of Using a Water Softener

1. It makes water safe for consumption and easy to use at home!

Soft water is safer to consume as compared to hard water. It is also safe and friendly to laundry and appliances. A water softener is responsible for softening the hard water making, which has a tendency of reducing the capacity of soap to react. Accordingly, it makes life easier and lengthens the lifespan of one’s appliances.

2. It eliminates the build-up of scales

As already mentioned, hard water stains appliances, toilets, dishes, sinks and pipes. Soft water eliminates the build-up of such scales and stains, effectively giving them a longer lifespan.

3. May put a strain on the plumbing system

Hard water could actually put the entire plumbing system under pressure due to the build-up of scales, ultimately destroying it.

4. Provides easy-to-use water

Soft water allows soap and detergents to work as they should and is comfortable on some people’s skin. Hard water is resistant to soaps, detergent and can irritate or feel dry to some people, especially their skin. The soft water also allows laundered clothes to appear shiny as they should. It softens one’s hair too.

5. For those who do not need sodium in water completely, it can be removed through reverse osmosis

Some water softeners might be criticized for producing water with too much sodium in it, which is not good for people on sodium-restricted diets. To counter this, the use of a reverse osmosis system effectively softens the water by removing sodium content completely.

6. Soft water can significantly reduce the onset and exacerbate eczema

It has been identified that high levels of hard water could contribute to eczema early in life. The use of hard water can also exacerbate eczema. Using water softener could hence stop or slow the development and worsening of eczema.

Disadvantages of Using a Water Softener

1. The end products may be too soft for some people!

The end product is soft water which for some, might be too slippery and slimy.

2. Too much sodium

Soft water from an ion exchange water softening contains sodium ions, which in some cases when not well managed might be too much. Some people may end up consuming 3,500 mg per day of sodium, which is higher than the recommended daily intake of 2,300 mg per day.

Although such amounts might not cause adverse health effects, it is still alarming that one could consume too much sodium from water softeners. Sodium in the softened water could also cause problems with septic systems.

3. Not suitable for irrigation

Softened water lacking calcium and magnesium elements but contains sodium is not suitable for irrigation. It is because it causes the development of alkali soils, which have a poor structure and cannot support irrigation.

4. They are expensive to install and maintain

Water softeners could cost at least $2,000 to install. They also require routine maintenance since the resin beads will eventually run out of sodium ions to counter the calcium and magnesium ions.

5. The alternatives are also expensive

The alternative to sodium or salt pellets in the tank is potassium chloride pellets. They eliminate the salt, but unfortunately, are expensive. For instance, where salt costs between $4 and $6 per bag, the same amount of potassium chloride goes for between $25 and $30.

6. Messing with dietary mineral requirements

There are some individuals who may require dietary supplements like calcium and magnesium, which is present in hard water but virtually missing in softened water. They, therefore, might mess with the dietary requirements by replacing those necessary elements.


Swistock, B. (12 July, 2011). Water Softening. Pennstate Extension Edu. Retrieved 12 March 2020 from https://extension.psu.edu/water-softening

Woodard, J. (11 Sep, 2019). What Is a Water Softener and How Does It Work? Fresh Water Systems. Retrieved 12 March 2020 from https://www.freshwatersystems.com/blogs/blog/5-benefits-of-having-a-water-softener

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About Rinkesh

A true environmentalist by heart ❤️. Founded Conserve Energy Future with the sole motto of providing helpful information related to our rapidly depleting environment. Unless you strongly believe in Elon Musk‘s idea of making Mars as another habitable planet, do remember that there really is no 'Planet B' in this whole universe.