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How does a water softener work?

Everything you need to know about the water softening process

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A water softener is a device or system that removes calcium, magnesium and other minerals from hard water. Minerals in hard water build up on bath fixtures and tile, clog plumbing systems, leave skin feeling dry and itchy, affect the efficiency and life of a water heater and leave spots on everything you wash.

Treating your water with a water softener or conditioner could be the right answer if you have hard water — one reviewer from California on our site who opted for water treatment saw great results: "my skin is not dry anymore. It's not itchy and my hair feels softer. Plus, my water tastes great."

Key insights

  • Water softeners typically take 85 to 90 minutes to regenerate.
  • You might spend between anywhere from a few hundred to several thousand dollars for a water softener.
  • Salt-free water softeners are actually more like water conditioners; they can't remove minerals from your water.

How do water softeners work

Typically, water softeners work through the process of ion exchange to turn hard water into soft water. Hard water contains calcium and magnesium, causing a wide variety of household issues due to mineral deposits left behind. An ion exchange water softener uses resin beads housed in the mineral tank to filter the water. The beads have negatively charged ions, while the minerals have positively charged ions.

As hard water passes through the mineral tank, the resin beads attract the hard minerals. The beads then shed off sodium ions in exchange for the calcium and magnesium ions to make the water soft. Later, the resin beads are cleaned of buildup using a solution from a brine tank.

Summary of how the water softening process works:

  1. Hard water enters through the main water pipe.
  2. The hard water flows into the water softener and into a mineral tank containing the resin beads.
  3. The resin beads collect the minerals and substitute them with sodium ions that soften the water.
  4. Captured minerals cling to the beads, leaving soft water to flow into the plumbing system.

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Water softener regeneration process

Over time the resin beads in the water softener become saturated with hard minerals and will need to be cleaned with a regeneration process to keep softening water. A strong brine solution from the brine tank is needed to rinse out the accumulated harsh minerals from the resin beads. The accumulated minerals exit through a drain. Regeneration is either a manual or automatic process. Manual regeneration requires you to physically start the regeneration of the water softener.

If your water softener regenerates automatically, it will either be a timed or on-demand regeneration cycle. With a timed cycle you will program how often your water softener regenerates. An on-demand cycle will track the amount of water you use and automatically start the regeneration process as needed.

Water softener regeneration steps:

  1. The backwash cycle reverses the flow of water to the tank to clean it from turbidity and other contaminants.
  2. A strong brine solution is created in the brine tank and injected into the resin tank to rinse the beads of the minerals.
  3. The brine solution carrying the hard minerals flows to a dedicated drainpipe.
  4. A slow rinse begins to allow the continuous flow of water to flush out the brine and any remaining hard mineral ions.
  5. A fast flow cycle follows to compact the resin bed and wash off the last of the brine and minerals.
  6. The brine tank is refilled with water to make it ready for the next service cycle.

How long does it take a water softener to regenerate?

A standard water softener should take about 85 to 90 minutes to regenerate. If your water softener takes three or more hours to regenerate or is continuously running even if water is not in use, it may be time to call for repair.

How often should a water softener regenerate?

Typically, regenerations can be set for every two to three days. However, there are several factors that need to be considered in determining when your water softener needs to recharge. If you own a pool or water your lawn frequently, you will need more frequent regenerations, maybe even several times a day. For everyday household activities, you won’t need as many regenerations. If you have very hard water, the resin beads in the water softener will become saturated more quickly than if your water is not especially hard. Iron in particular can prove problematic for water softeners, requiring them to regenerate more often. As your water softener ages, it will require more regenerations. Larger water softeners require fewer regenerations because they have more resin beads.

How much is a water softener?

A water softener that regenerates manually costs around $400, plus an additional $200–$300 for installation. A water softener with a timed or metered system runs between $2,000 and $4,000. Some can cost as much as $10,000. Factors that affect average water softener cost include plumbing system size, age of the building and number of users.

Additional factors that affect water softener prices include the salt, water and energy needed to operate. Salt typically costs just a few dollars per person each month. Water softeners generally use little energy, so the costs associated with powering them are minimal.

How long do water softeners last?

A water softener typically lasts for 10 to 15 years. This varies depending on type, quality, age and maintenance. You can help ensure a long life for your water softener by adhering to maintenance best practices.

Water conditioner vs. water softener

Water softeners convert hard water into soft water. A water conditioner, on the other hand, is a more general term for a water filtration system that removes chlorine and other contaminants. If you’re finding that hard water is causing problems like funny-tasting water, stains on dishes or clothes not being fully cleaned, then a water softener could help you. If you are looking to reduce the amount of chlorine or other contaminants in your water, try looking into water conditioners.

A water conditioner is a system that changes the chemical structure of water to prevent minerals from forming scales, spots and watermarks, but it does not remove those minerals. For example, a water conditioner can filter chlorine from water to make it more palatable, but it cannot remove calcium or magnesium.

A water softener is a water treatment system that softens hard water by removing certain chemicals and minerals and replacing them with sodium ions through ion exchange.

You may hear about “salt-free” water softeners. These have certain benefits, but they are incapable of removing minerals from hard water. They are more similar to water conditioners than water softeners.

Whether you want a water softener or water conditioner depends on if you want to actively remove minerals from hard water.

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Bottom line

Water softeners offer homeowners a convenient solution to the problems that come with hard water. Water softeners ensure that water is continuously kept soft for spotless bath tiles, sinks and kitchenware, cleaner laundry, and softer skin and hair. The low costs of operation and clear benefits make water softeners a great purchase for any home that has hard water.

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