How does a water softener work?

If you have hard water you’ve probably heard that a water softening system could be saving money, but how does a water softener work?

Hard water is a slow and silent killer (of your plumbing and appliances).

Hard water is expensive, by corroding your plumbing and shortening the lifespan of your fixtures, pipes, water heater, and appliances.

Hard water also leaves tough-to-clean limescale deposits on baths, toilets, sinks, and faucets.

A whole house water softener exchanges the hard water mineral ions for sodium or potassium ions that provide you with soft, luxurious water.

The process is called ion-exchange. It’s using positive and negative electrical charges to replace undesirable contaminants in the water with more desirable ions.

What is hard water?

Most household tap water comes from city water systems that started its path to you as either groundwater or surface water.

Groundwater is found underground in aquifers that get filled from melting snow and rain.

Surface water is collected mainly by rains and groundwater deposits that have risen and reached the surface.

A city or town collects and then treats both forms of water, and it’s circulated through a vast plumbing network, bringing water to your home.

In many cases, the municipal water fed to your home is hard water.

Hard water is a term used to describe water that contains an unusually high amount of dissolved minerals such as calcium, magnesium, iron, etc. Water can absorb these minerals from the surrounding rock and soil when it’s still underground or flowing through piping.

The scale of water hardness depends on how many grains of these minerals are absorbed. Water hardness is measured in grains per gallon (GPG) and milligrams per liter (mg/L). The higher the water hardness, the more corrosive on appliances and plumbing, and the worse it will taste.

0 to 60 mg/L is considered soft water, which is where you would like your home’s water to be. This “soft water” still contains essential nutrients for your body, but without the high amounts of unwanted heavy minerals.

The next level is moderately hard water, which ranges from 61-120mg/L.

Then hard water is categorized as water containing 121-180mg/L. Hard water will cause severe corrosive problems in your household plumbing and appliances.

Anything above 180mg/L is very hard water.

Here in Riverside County CA, most of us have “hard water” or “very hard water” coming from the city into our homes.

If you have “hard water,” just about everything in your home is at risk. What’s not in the plumbing is still subject to leaks and floods due to hard water corrosion.

Hard water can be challenging to spot at first, and the problems can go unnoticed. Some of the corrosion it causes shows up fast, like limescale stains on showerheads and faucets, or soap scum on shower doors, tile, and baths.

The more costly damages take a while to develop; such as corrosion to your plumbing, water heater, washing machine, dishwasher, and other appliances, etc.

Other immediate hard water issues are soaps and shampoos not lathering properly, soap scum film on your body and hair after showering and on glasses after running the dishwasher, and the need to use more soap to get things clean.

The problems caused by hard water can add up quickly cost both your home and your wallet over time.

Water is such an essential aspect of everyday life, and we don’t even realize it half the time. The last thing people would think about is if your water is doing you or your home any harm, but if you have hard water, it is quietly doing just that.

Infographic - How to Test for Hard Water

How to test your water

You can buy hard water test strips from most home improvement stores. These will usually be able to test the pH level, chlorine, and more.

A more accurate measurement can be made by a TDS Meter to test your water, which you can buy on Amazon. A TDS Meter is a handheld device that’s used to measure the Total Dissolvable Solids in your water. This TDS meter is a helpful tool in measuring how much of your water isn’t water.

A TDS Meter measures anything dissolved in your water by how conducive these sediments are. It measures anything in the water that’s conducting electricity, not necessarily just minerals that are causing water hardness.

To obtain the most accurate reading, you can always use a professional water testing company or laboratory. A water testing lab will provide the most precise way to get your water tested but is somewhat unneeded. If the test strips tell you that you have hard water at a high level, then you have hard water.

Knowing the exact level is not as essential because whether your hard water is at a low or a high level, the consequences are still the same.

If you are in the range of hard water, you will want to take the next step in fixing the problem. Yes, you guessed it, by using a water softener.

What does a water softener do?

A water softener extracts the unwanted minerals from your hard water, making it softer and cleaner. The water softener unit is connected directly to your water supply.

The actual process of water softening takes place inside this unit. The process is called ion exchange, and it sounds a lot more complicated than it is.

Infographics: How a water softener works

How does a water softener work?

The process of softening water consists of two steps. First softening the water, and then regeneration.

The water softening process is relatively simple. As water enters the water softening unit, it passes through a tightly-packed resin bed.

This resin bed is filled with tiny resin beads that contain sodium or potassium ions.

The beads absorb the unwanted hard minerals in your water by exchanging sodium ions for the heavy mineral ions and allowing luxuriously softened water to pass through to your home.

The result of that science is luxurious-feeling water that softens your skin and hair.

Soft water that no longer corrodes your pipes, faucets, and appliances or leaves limescale buildup behind.

After a measured volume amount of water has flowed through the ion exchange / softening tank, the beads need to be regenerated.


The next step is regeneration.

The beads eventually need to be cleaned to discard all the heavy minerals they’ve absorbed, then get recharged with fresh sodium or potassium ions.

This regeneration process is pre-set into the system’s timing mechanism and will automatically occur after a specific volume of water has gone through the tank.

The process starts with a backwash flush to remove the heavy minerals from the beads

Next, water runs through the smaller tank, which contains sodium or potassium salt, to create a brine wash that flows into the taller ion exchange tank to coat the beads with fresh sodium and potassium ions.

Now your water softener unit is back to full strength and ready to go.

How often does a water softener need to regenerate?

There are a few variables that go into how regularly your water softener regenerates.

First, there are a variety of water softener units available on the market. Each one has the same basic science behind it, but capacity and level of technology may vary, which would determine how often a system needs to regenerate.

Older systems would regenerate by time, which is not accurate enough and these systems often either wasted water and brine or didn’t regenerate enough.

Today’s more advanced systems regenerate based on the volume of water used (in gallons), which is the preferred method.

Can a water softener save you money?

Yes, if you have hard water, a water softener can save you money.

Water touches just about everything in your house. From your pipes to your clothes, food, and oh yeah, most importantly, you.

Maintenance or replacement of your faucets, shower-heads, toilets, washing machine, dishwasher, water heater, and more can be expensive.

The costs of reduced lifespans due to corrosion on your appliances and plumbing can add up quickly.

You will end up having to replace most of these appliances at some point, but with hard water, you can expect to cut the lifespan of your appliances by nearly half.

In terms of personal care, you would be surprised at the money you can save on soaps and detergents.

You may not notice it, but you use a lot more soap with hard water because it doesn’t create suds properly in hard water.

Most people don’t realize at first, just how much money hard water is costing them over time. But these things add up and turn into very costly expenses.

Pros of water softening:

  • Saving appliance lifespan
  • Saving water heater lifespan
  • Less harsh on clothes
  • Saves money on maintenance & repair of plumbing
  • Allows soap to work correctly, so you save $ on soaps
  • Costs less than $10 a year in electricity

Cons of water softening:

  • Adds sodium to your water (a minimal amount that is not significant to a percentage of your daily recommended intake).
  • Uses more water for regeneration cycles.
  • Cost of sodium or potassium salt ($5 /month avg).


Infographics - Hard Water Myths


Is it safe to drink water from a water softener unit?

The answer is YES. Your water softener unit will be getting rid of harmful minerals in your water to give you cleaner drinking water. Instead of drinking hard water laced with heavy metals, you’ll be drinking cleaner, softened water.

The amount of sodium or potassium is negligible, and you will not taste it. In fact, the water will taste better because it no longer contains all of the heavy metals it used to.

Important: If you or anyone in the household is on a low-sodium diet, it’s recommended you use potassium salts in the brine tank instead of sodium.

Also, consider using a whole house filtration system or reverse osmosis system at your sink to also remove the sodium or potassium.

Is a water softener also a water filter?

No, for truly safe drinking water and water to cook with, we recommend also installing a whole house water filtration system.

Only a whole house water filtration system will remove 99.999% of lead, arsenic, and other particles and destroy and remove any harmful bacteria or other organisms.

How long does it take a water softener to work?

For cold water, you will get soft water immediately after the installation of your new water softener unit. There will be no wait time after installation.

For hot water, it may take a little bit more time if you have a hot water tank.

Will my water softener get rid of essential minerals in my water?

No. Water softener targets specific hard minerals that are not supposed to be in your water supply.

They do not filter out any other minerals that are good for your water. Not only will they not get rid of essential minerals, but the system is also adding trace amounts of valuable nutrients, sodium or potassium.

Will a water softener be expensive to run?

Just the opposite actually, a water softener costs only about $10 a year in electricity to run and $50 to $100 a year in salts.

Over time, a water softener can save you a ton of money by extending the life of your plumbing fixtures, pipes, and appliances. It also reduces the number of soaps and detergents you’ll need to use.

What size softener do you need?

See our article entitled, “How to Size a Water Softener.”

Get a quote!

See our water softener service page.

Residential Water Softener Guidelines (City of Riverside CA)

Hardness of Water (USGS)

Water Softening (Penn State University)

Follow Us
Owner - Operator at RT Olson Plumbing
Bob Olson has over 18 years experience in all aspects of residential and commercial plumbing. He's a 4th generation plumber. With over 500 five-star customer reviews, he runs one of the best-rated plumbing companies in Corona, CA.
Bob Olson
Follow Us
Latest posts by Bob Olson (see all)
Book Online Now