How Does a Water Softener Work?

Written by Cory Stutzman

Curious about how a water softener works? Here’s a simple explanation!

From the Kinetico Website: Hard water is softened by removing the calcium and magnesium it contains. When hard water passes through the softening system’s resin bed, the calcium and magnesium (hardness) ions are removed through an ion exchange process, so only softened water passes through to your home. Once the resin bed fills up with hardness ions, it must be regenerated (cleaned). Salt is typically used in the regeneration process and restores the resin to a “clean” state so the ion exchange process can begin again.

Pretty simple, right? Well, if you’re not fully versed on resin beds, ion exchange, or the process of regeneration, this might still be a little confusing.

Popular Mechanics refers to water as a tool. It’s “a fluid medium that carries material from one place to the next…and one of the reasons it does this job well is that it’s very good at holding things, either by suspending them or dissolving them”. There are usually dangerous chemicals that make groundwater unfit to drink. There are also harmless minerals that make your water “hard” and can cause problems in the home.

Hard water doesn’t dissolve soaps effectively, so more is required to do the job. It causes soap to “cling” to your skin and hair, causing dryness and other undesirable effects. Laundry soaps used in hard water can leave behind traces of dirt and other bacteria; clothes and other fabrics probably aren’t getting as clean as you think they are. Calcium and magnesium deposits found in hard water can build up in pipes and generate scale buildup in water heaters and, over time, ruin both.

So what do water softeners actually do? Popular Mechanics makes it easy to understand – “they trade the minerals for something else, in most cases sodium”. This is the ion exchange process. The water softener’s mineral tank contains resin (polystyrene beads) which carry a negative charge. Calcium and magnesium in water both carry positive charges. The minerals latch on to the resin as the water passes through the mineral tank and these positive charges are then replaced with the positive charges found in the sodium from a strong brine solution, which is created in a separate brine tank using water softener salt and back-washed into the mineral tank. The sodium basically drives out the calcium and magnesium from the beads, resulting in sodium rich ions. The sodium attaches to the resin, replacing the calcium and magnesium, and the “hard” minerals go down the drain. Once this cycle is complete, the mineral tank is flushed of excess brine and the brine tank is refilled.

Hopefully this explanation helps without bringing back too many memories of high school chemistry class. If you would like more information on how a water softener can benefit your life, please contact your local Water Specialist with questions.