How does a water softener work and why are they used in homes?!

Before getting into detail about how do water softeners work, let's clear this one up first, a water softener is not a water filter and does not improve water quality.

A water softener does one job, it removes the dissolved minerals calcium carbonate (CaCO3) and magnesium carbonate (MgCO3) from water.

These are often known as “hard ions”. An ion is an electrically charged atom or, in this case, molecule.

How do water softeners work?

A very simple explanation on how a water softener works is that water containing hard ions flows through a vessel containing resin beads that are high in sodium ions.

These beads attract and hold the hard ions and release the sodium ions into the water instead.

The water then flows out of the vessel having had the hard ions removed and so is “soft” and continues into the household pipes ready for use.

Obviously, there's a bit more to how water softeners work because after a short time the resin beads become saturated with CaCO3 and MgCO3 ions and the process stop working. This is when the water softener starts regenerating.

Further down this article, we provide a detailed, step-by-step explanation of how water softeners function.

Why do water softeners regenerate?

Yes, water softeners regenerate… but why? The explanation is that once the resin beads reach their saturation point, which usually only takes a few days, the softening process will become less efficient, until it stops completely. The consequence of this is that you will be left with hard water and will have to deal with all that limescale build up again.

To make water softeners continue working efficiently they have a regeneration system built in.

This is where a tank of highly concentrated brine is used to reverse the softening process and dump all the hard ions and salty wastewater to the drain.

It usually takes about two hours and is programmed to happen in the middle of the night when no one is using any water.

The great thing about this regenerating “backwash” cycle is that it means that water softeners can continue working for years and years - so long as they are maintained.

Why do water softeners need salt?

The reason why water softeners need salt is that the brine used to carry out the backwash cycle is highly concentrated salt in water.

To maintain that brine concentration, salt pellets must be put into the system regularly.

Adding salt in a water softener can be as often as every three days for some water softener systems; it varies depending on what type of regeneration system is used, and how big the reservoir is.

There are two kinds of backwash processes in water softener systems:

1. Counter-current regeneration system:
   In a counter-current regeneration system the brine solution is fed through the system in the opposite direction from the usual water flow. The counter-current water softener regeneration system is more efficient and therefore uses around 75% less salt and 65% less water to complete the cycle.
   These are often called “high efficiency water softeners”.
2. Co-current regeneration system:
   A co-current regeneration system the brine flow is in the same direction as the normal water flow direction.

How does a water softener work step by step?

Having examined the principles of how water softeners work, let's go into detail and explore how a water softener works step-by-step:

1. Hard water from your mains supply enters the water softener vessel.
2. Resin beads in the vessel attract the hard ions - mainly CaCO3 and some MgCO3 - and keep hold of them, thereby removing them from the water.
3. Soft water is released from the vessel and flows into the household water pipes.

Next, there's the regeneration (or backwash) cycle of the water softener, which proceeds as follows:

1. A concentrated brine solution is created by adding salt to water in a brine tank.
2. That brine then flows through resin which strips the hard ions, replacing it with sodium ions thereby rinsing away all the hard minerals.
3. The brine solution which now contains all those hard ions are flushed away to the drain.
4. The resin beads are now replenished and ready to continue their job softening the water.

How do electronic water softeners work?

Devices labelled as electric water softeners don't truly soften water, as they do not eliminate the calcium carbonate or magnesium carbonate dissolved in hard water.

These type of water softeners claim to alter the ionisation properties of the dissolved minerals so that it prevents them causing scaling.

The theory is that a coil of insulated wire is wrapped around the incoming mains water pipe. This is then connected to an electrical supply to create a magnetic field that passes through the water.

How do magnetic water softeners work?

Magnetic water softeners are very similar, or even the same as electronic water softeners.

The main difference between magnetic and electronic water softeners is that magnetic water softeners wrap the water pipe in a magnetic sleeve; that may be an electromagnet that may require a power supply.

Again, the theory is that the magnetic field realigns the charge in the hard ions so that they don't form scale.

There's not much empirical evidence that categorically verifies that either of those systems actually work well.

But many people who have them swear that they do.

There are other salt-free systems that minimise, reduce, or completely eliminate scale formation caused by hard water.

Sequestration using polyphosphate often works for medium hard water areas.

Then there's the media assisted crystallisation (MAC also known as TAC) which has been independently verified to be highly effective (see WateReuse Foundation's study - page 43 shows the overall results).

This innovation was first introduced in 2010, and has proven popular since Fountain Filters were shown the Watts OneFlow System in 2015.

No matter what your requirements are, we can assist you in finding the appropriate solution for treating your hard water. As water filtration specialists, we have a wide range of water softeners to suit different households and water hardness levels.

 

And if you get in touch with Fountain Filters, we will pay close attention to your needs and offer you options tailored to your specific circumstances.

 

FAQs

Is a water softener the same as a water filter? No. A water softener only removes the dissolved hard minerals calcium carbonate and magnesium carbonate from water - it does not improve water quality or filter out anything else.

Why do water softeners need salt? The regeneration (backwash) cycle uses a highly concentrated salt brine solution to strip the hard ions from the resin beads and flush them away, so the salt needs to be topped up regularly - sometimes as often as every three days, depending on the system.

Do electronic and magnetic water softeners actually work? They don't remove hard minerals in the way a traditional salt-based softener does - they claim to alter the ionisation properties of the minerals to prevent scaling. There isn't much empirical evidence that categorically verifies they work well, though many users report good results.

Are there salt-free alternatives to a traditional water softener? Yes. Options such as polyphosphate sequestration (for medium hard water) and media assisted crystallisation (MAC/TAC) can minimise, reduce, or eliminate scale formation without using salt; MAC/TAC has been independently verified as highly effective.