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How Do Water Softeners Work?

How Do Water Softeners Work

Water softeners address one of the biggest water problems: hard water. Hard water contains calcium and magnesium minerals, which produce something called scale, which causes all kinds of issues around the home. As well as clogging plumbing, hard water scale also lines the surfaces of water-based appliances and reduces their lifespan, making them efficient and more prone to breaking down.

How does a water softener work? If you’re considering buying one for your home, you’re probably keen to learn the exact process you can expect from a standard salt-based softener. Once you know the science behind soft water, including what causes hard water and how to get rid of it, you’ll be a lot better equipped to make the right purchase based on your water softening needs.

What are the parts of a water softener?

Salt-based water softeners are the most popular systems for softening water, with a scientifically-proven softening process to support their effectiveness. They’re made up of three main components:

  • A mineral tank (otherwise known as a resin tank)
  • A brine tank
  • A control valve

The mineral tank is where the actual water softening takes place. In this tank, which is filled with beads known as resin, the hard water minerals, calcium and magnesium, are replaced with soft water sodium ions.

The brine tank is where the sodium, or salt, is stored for use. The salt mixes with the water at the bottom of the tank to form a brine solution. When the mineral tank needs to regenerate, the brine tank is used to flush out the hard water ions. It’s important to top up the brine tank with salt when the salt levels fall low.

Finally, the control valve controls how much water flows in and out of the mineral tank and brine tank, ensuring proper regeneration and enabling the system to be efficient.

Water softening process

The water softening process begins when water enters the water softener through the main water line. It passes into the mineral tank, which is where the softening can start. The resin beads in the mineral tank are negatively charged with a sodium ion.

When the resin comes into contact with the positively charged calcium and magnesium minerals, which are also in an ionic form, it attracts the ions and traps them, preventing them from being able to pass through the system with the water. When this happens, the resin beads will release the sodium ions, replacing the hardness minerals with sodium ions.

Does the average water softener reduce iron? Yes – because water softeners are capable of attracting and holding onto any positively charged ion, many systems are also able to reduce or remove iron from water, which is also found in ionic form. Iron is a particularly annoying contaminant as it’s known to cause staining on plumbing appliances, and can affect water taste and flavor in some forms. Just like it can replace calcium and magnesium ions with sodium ions in the ion exchange process, a water softener can do exactly the same with iron.

water softening process

Regeneration process

When the resin beads in the mineral tank become saturated with calcium and magnesium ions, the system will need to regenerate, and this is where the brine tank comes in use. When the mineral tank needs backwashing, the tank will fill with a sodium brine solution, which will remove the minerals and restore the resin beads back to a negative charge in a process called recharging, ensuring the resin is ready for reuse.

It’s important for the brine tank to constantly topped up with sodium (salt), so there’s always enough sodium in your brine solution to remove the hard water minerals in ion exchange. You can buy sodium for water softeners online, and many companies offer great deals for bulk-buying the stuff.

Your system wouldn’t know when to regenerate without the control valve. This clever technology monitors your water usage and determines when it’s time for the system to flush out the hardness-saturated resin and replace it with negatively-charged resin. Once the resin is removed from the system, it is flushed down a drain, which is connected to your home’s sewer or wastewater system.

Finally, the system rinses itself out with water, before the softening process can begin again.

regeneration process

Additional considerations

There are several other factors to consider when it comes to how a water softener works. Here’s what else you may need to know:

Salt-based vs salt-free

In this guide, we’ve focused solely on salt-based water softeners, otherwise known as ion exchange softeners, as these are the most popular (and some would say most effective) available today. But there are other types of softeners that are rapidly gaining popularity, especially salt-free water softeners.

This type of softener, as the name suggests, uses a salt-free process to soften water. For this reason, it’s advertised as a better option for people on a low-sodium diet, or people who just won’t want to add salt to their drinking water.

Salt-free softeners don’t actually remove the hard water-causing calcium and magnesium ions from water. Instead, they use a chemical process to transform the calcium and magnesium, giving them a different structure that prevents them from being able to bind to surfaces in the form of limescale. Salt-free softeners aren’t technically considered water softeners; rather, water conditioners, as they don’t actually remove the calcium and magnesium ions from water.

Single vs dual tank

The majority of water softeners are dual tank, or twin tank, which means the system has two tanks, making the entire softening process more efficient. This is because one tank can regenerate while the other takes over with water softening. If you’re looking for a water softener that’ll work 24 hours a day, a dual tank softener is for you.

It’s best to get a dual tank water softener that will regenerate as and when needed than to get a single tank softener that regenerates on a timer. Using a timer-based regeneration instead of letting the system regenerate when it needs to means your water softener won’t be anywhere near as efficient as it could be, as it’ll be regenerating needlessly, even when there are still free resin beads in the mineral tank.

Conclusion

Many people ask whether water softeners are really necessary. The answer to this is: it depends. If you’re looking to extend the lifespans of your water-based appliances, save yourself on hours of cleaning, improve water’s ability to lather and prevent staining on your glass fixtures and dishware, you’ll appreciate the benefits a water softener can bring to your home.

Having a clean water supply will mean far less maintenance and money spent on your end in the long run, which is an attractive prospect to anyone who plans to live in their home for the foreseeable future. Water softeners work very effectively for their price, and you can usually get a great deal on a system that will last you for years and years with minimal maintenance. For the majority of people who invest in a water softener for their home, the money spent is more than worth it for the softened water benefits they can enjoy.

Further info: How to select the right size water softener