With more than 30 years’ experience in the residential and commercial water treatment space, Mark Nelson is a Class 1 Drinking-Water Operator and a CBWA (Canadian Bottled Water Association) Certified Plant Operator. As founder and president of Nelson Water in Ottawa, Mark focuses on dealing with challenging water treatment system designs for problem water. He also heads the largest water bottling plant in the city of Ottawa with a delivery network throughout the Valley.

If you have hard water supplied to your home, you already know about the negative effects that it has on many aspects of your home life. Hard water contains elevated concentrations of dissolved minerals, including calcium, magnesium, and to a certain extent, iron too. When water is hard, it’s harder to use, it dries out skin and hair, clothes are harder to wash, the plumbing system can be corroded, and scale can accumulate in water using appliances. For these and other reasons, many people install a water softener to remove the hardness. In this article, we will take a closer look at how a water softener works to help you make informed choices.

Why is Water Hard?

Water is an effective solvent; after it falls as rain, it seeps into the ground and passes through various layers of soil, sand, and rock. The properties of these materials are added to the makeup of the water, and this includes the dissolved minerals. The only practical way to remove hardness from your water is to use an ion-exchange water softener.

How Does an Ion-Exchange Water Softener Work?

Before we begin, it’s important to note that there are a number of water softeners on the market that use alternative processes to remove the dissolved mineral content. But, the most reliable and widely used method is the ion-exchange process, and that will be the focus of our article.

The setup of an ion-exchange water softener relies on a media tank filled with resin balls. This is where the incoming water undergoes the ion-exchange process. The resin media tank is connected to a brine tank that contains a salt solution. The water softening salt added to the brine tank may be sodium or potassium-based.

The incoming water comes into contact with the resin media balls that are charged because they are coated with salt from the brine solution. The dissolved minerals in the hard water also have a charge, and they are attracted to the charged resin media. As the mineral ions adhere to the resin media, they are exchanged for the salt ions on the surface. This is the ion-exchange process; the mineral ions are essentially swapped out for the salt ions. This exchange takes place on a minute scale, some saltiness is added to the water, but most people wouldn’t notice any difference.

The Regeneration Cycle

After repeated ion-exchanges the resin media ball surfaces are coated with a layer of mineral ions. Gradually, the surface becomes clogged, and the resin media may be unable to receive a coating of brine to charge it for the ion-exchange. So, the system will become less efficient at removing the hardness from the incoming water. To deal with this problem, the water softener has a regeneration cycle to clean the resin media and recharge it. The media is flushed with brine using a control valve that has a timed or demand-initiated system. This removes the mineral ions and directs them into the drain. The clean resin beads are then coated with brine to begin the ion-exchange process again. The regeneration cycle takes place at times when people are asleep to minimize disruption. This is necessary because the system is placed into bypass mode until the regeneration cycle is completed. So, if you were to rise too early and take a shower, you may be showering in hard water if the regeneration cycle is still running.

Do I Need a Water Softener System?

This is a question that only you can answer. If you receive hard water, you will spend more on soap and detergent because hard water minerals inhibit the formation of soap suds. The accumulation of scale on heating elements and inside plumbing pipes will cause damage that’s expensive to fix. Water using appliances will fail more frequently, and the useful lifespan may be lowered. Although the upfront costs of a water softener may seem daunting, they tend to pay for themselves quickly.

Which Contaminants Can an Ion-Exchange Water Softener Remove?

A water softener is only designed to remove dissolved calcium and magnesium ions from the water. The ion-exchange process will attract positively charged ferrous iron (a cation) to a certain extent. It is possible to install a water softener with a built-in iron filter if you receive water with high iron concentrations. But, if the concentration of iron is very high, many people install a dedicated iron filter to deal with that specific contamination problem. A water softener will not remove any other contaminants, and it’s typically installed in series with other water filtration and purification systems. The exact processes used and the configuration of these systems will be determined by your specific water contamination issues. For this reason, we recommend professional water testing to fully understand the makeup of your water supply. This information is important when you’re making decisions on the water treatment systems you need for your home.

Is Soft Water Safe?

Yes, soft water is safe for drinking, cooking, preparing food, cleaning, and any other tasks that require clean water. It is true that a minute volume of salt (sodium or potassium) is released into the water during the ion-exchange process. But, the volume of salt added will be determined by the hardness of your water. To put this into perspective, let’s take a look at an example:

If you received water with 5 grains per gallon (gpg,) it would be classified as moderately hard water. The salt ions added to make the water soft would be around 37 milligrams (mg) per quart of water. If you’re using a sodium-based water softener salt, this would be less than 2% of the daily recommended salt intake. To put this another way, a slice of pizza contains 640 mg of sodium, and a single slice of white bread contains around 170 mg of sodium.

As you can see, the volume of salt added to the water is negligible. But, if someone in the home is on a strict low-sodium diet, it’s a good idea to use a potassium-based water softening salt. Using a potassium-based product is slightly more expensive, but it’s more benign in nature than a sodium-based softening salt. If you’re concerned, consult your doctor for more information.

If you’re considering an ion-exchange water softener installation for your home, contact your local water treatment specialist for more information.