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Water Softener regeneration Process: Frequency & Problems

Scott Winfield
Written by Scott Winfield
Last Updated on

If you’ve been researching water softeners, you’ve probably come across the term “regeneration process” many times. Naturally, you’ll be wondering what on earth it is and how it works.

To get you up to speed, we’ve put together this in-depth guide on the water softener regeneration process. We explain what it is, why it’s important, and how often it happens. We also troubleshoot common regeneration problems so you can keep your water softener running smoothly.


What is Water Softener Regeneration?

Water Softener Regeneration Process
Water Softener Regeneration Process: Photo Credit – https://www.apswater.com/images/regen.jpg

Water softener regeneration is the process of flushing out the calcium and magnesium hard water minerals that build up in the softener’s resin bed. This also recharges the resin beads so that they can effectively remove hard water minerals from your water.

Why It’s Important

A water softener works through ion exchange, a process in which positively charged mineral molecules are attracted and trapped by a negatively charged resin bed. This bed replaces the “hard” magnesium and calcium ions with “softer” sodium ions.

However, the resin bed can’t maintain its negatively charged sodium status forever. After a while, it becomes saturated with all the calcium and magnesium molecules it traps.

So, to continue functioning properly, the system needs to clean and recharge the resin bed every once in a while. To that end, most traditional softening units feature two tanks: a resin tank where the softening happens, and a brine tank that provides a brine solution used to flush out the resin bed.

Most devices come with a pre-programmed regen time determined by the hardness of your water and the capacity of the device. When that regen time comes, the brine solution starts making its way through the whole system, sending trapped minerals down the drain and recharging the resin bed.

The Water Softener Regeneration Cycle

Here’s how the regen cycle works:

  1. The water softener cleans hard water
  2. The water softener’s resin bed gets saturated
  3. The water softener switches frequencies and needs to be regenerated
  4. The water softener opens the brine tank and uses a salt block to prepare a brine solution
  5. The water softener flushes through the salt block, cleaning out the resin bed
  6. The water softener flushes through the entire tank, cleaning it and rinsing out excess salt
  7. The water softener switches back to its original settings
  8. The water softener starts to soften hard water again

Each of these steps happens automatically except for salt block renewal. As a water softener owner, it’s your responsibility to add salt to the brine tank. If you’re experiencing a downtick in water quality, it might be because your water softener is out of salt.

You can find the best salt for your softener in the device manufacturer’s online store, but local appliance stores also provide a variety of options.

How often you need to replace the salt depends on your water hardness levels and the quality of the salt you use. However, it’s typically best to replace the salt around once a month.

If you have a new water softener, it’s a good idea to ask the manufacturer how often you’ll need to replace the salt for your unit.

Water Softener Regeneration Frequency – How Often Should it Regenerate?

Water softeners regenerate once a week. Usually, they do this automatically and in the early hours of the morning or during the night.

During the process, water flow is greatly reduced meaning the softener is essentially out of operation. This is why most units are pre-programmed to regenerate at times when the water demand is usually at its lowest.

Although water softeners typically regenerate once a week, they can regenerate more or less often, as needed. The schedule depends on the type of water softener you have, as there are models with time-initiated or demand-initiated regeneration.

Time-initiated regeneration flushes the water softener after a certain amount of time (usually once a week). It’s controlled by a small timer on the side of the softener and automatically resets once it’s regenerated.

Demand-initiated regeneration measures the amount of water that passes through the softener. Once a set amount of water has been softened, the system regenerates automatically and starts over.

You can also program regeneration cycles manually. This is particularly useful when it’s time to clean your water softener. As long as you follow the steps in your unit’s instruction manual, it’s a fairly easy procedure.

How Long Does Regeneration Take?

A water softener takes 30 minutes – 2 hours to complete regeneration depending on its size and capacity.

Although the process itself may seem straightforward, it’s actually more complex than a simple flushing. The brine solution needs ample contact time with the resin to dismantle trapped minerals and feed it an adequate amount of new sodium ions.

Units with large tanks also have large resin surface areas. This means more contact time is required, which increases the length of the regeneration process.

Some innovative devices have an upflowing process, while most traditional ones have a downflowing one. During an upflowing regen, the solution enters the resin tank from below and moves upward, lifting the resin up. During downflow regeneration, the resin remains stable.

By lifting the resin, upflowing regen allows the solution to have more contact surface with the resin in less time compared to downflow. So, the uplfowing regeneration process is generally faster and more efficient than the downflowing process.

Almost every water softener brand on the market provides information on the regen time of their devices, so you can check this before making a purchase.

Can You Use a Water Softener While It’s Regenerating?

Water Softener Tanks
Water Softener Tanks

Generally, you can’t use a water softener while it’s regenerating. This is because most systems have a single resin tank that needs to be flushed during the process. The resin tank can’t continue to soften water while this happens.

If you do use a water softener while it’s regenerating, it might still work to some extent. But, you’ll experience very low water pressure and the water it provides will be quite salty.

However, some units come with dual resin tank setups or specific water reservoirs so that the regen process doesn’t affect water use. If you have a dual-tank system, then you can use the softener as normal while it regenerates.

How Much Water is Discharged From a Water Softener During Regeneration?

The volume of water a softener discharges during regeneration can vary widely between different units. Some smaller systems may only discharge around 4 gallons of water while large units can discharge up to 70 gallons.

This water is the result of two different rinse stages:

  • Brine rinse: Once the resin bed has been flushed with brine solution, the remaining brine and captured hard minerals are rinsed away. This water is then discharged into the drain.
  • Fast rinse: The softener then performs a final rinse with clean water to remove any remaining residue, and this water is also discharged into the drain.

Unfortunately, the discharged salty water from the regeneration process can be bad for the environment as it can leak into freshwater sources and harm aquatic life. To reduce the environmental impact, try to choose a water softener with a highly efficient regeneration process.

Common Regeneration Problems

Of course, no machine runs smoothly forever. As with all appliances, there are common issues that prevent softeners from operating efficiently. So, let’s see why they occur and what you can do to deal with them or prevent them.

Water Softener Rusty After Regeneration

If your water is brown or tea-colored after regeneration, your unit might require a little extra cleaning to avoid rust. Iron is the most common element on earth, and although most water softeners remove iron, when there’s more iron than 2 to 5mg/L in your water supply, it might still leach into the end product.

What’s worse, exposing the device to more iron than it can handle will quickly render the device ineffective since the excess iron will build up on the resin tank. Eventually, the brine solution won’t be able to flush it all out and it’ll show up in the water coming out of your faucets.

To avoid this problem, use an in-depth resin cleaner, like Iron Out, on top of the regular regeneration cycle. This chemical formula will strip the rust and leave your resin sparkling clean again. You can head to our guide on how to clean a water softener for more info.

That being said, if the water supply is especially rich in iron content, the best course of action is to complement the softening device with a whole-house iron water filter.

Water Softener Stuck in Regeneration Mode

Although water softeners automatically switch in and out of regeneration mode, the timing mechanisms aren’t always perfect. Sometimes they get stuck or broken, and the softener keeps regenerating and never softens the water.

In such cases, the first thing you need to do is bypass the softening device and unplug it. Then, you can call customer support and learn about the manufacturer’s recommended course of action.

They’re likely to send a technician, who will probably advise you to replace the device’s timer. Depending on the manufacturer, technician, and problem, the expenses might range between $100 and $600.

Water Softener Making a Loud Noise During Regeneration

Water softeners typically aren’t very loud while regenerating. However, some can create a loud banging or mechanical sound as the unit resets.

For the most part, this is normal. It could just be the system resetting or the valve switching. However, if it bothers you or happens continually, you might need to call a technician.


The regeneration process is absolutely vital for ensuring your water softener works effectively. This process usually occurs once a week, typically when the water demand of your household is at its lowest, and, depending on the device, it lasts 30 to 120 minutes. When it’s time to clean the device, you can run your own manual regen cycle by consulting the instruction manual.

Although the device will usually still have water available during regen, albeit at a low pressure, we don’t recommend using water within that period. If the device takes too long to regenerate, gets stuck in the process, or makes particularly loud noises, you should call a technician.

On the other hand, if the water is brown, it indicates rust buildup in the system. You can take care of the rust problem with resin sanitizers, and you can install an iron filter to prevent further occurrences.

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Scott Winfield
Scott Winfield
My name is Scott Winfield and researching and writing about water filters and other strategies to purify water has become my full time passion in recent years. I'm glad that you found our site and you can look forward to authoritative and well researched content here to help you get the best in water.
  1. My water softener, possibly a Sentry II 960, is not working. I took out most of the salt to check the water level which is about 6″. I went to Regen and the brine tank was empty in about 10 minutes of a 60 minute regen cycle. I am wondering if it uses so much water because the resin is gone or shrunk so that channels are forming through it.

  2. What causes the time to change for regeneration? Ours used to go through the process @ approximately 2:00AM.
    It changed to doing the process in the afternoon. We did not make the change & we are in Arizona so there is no change to DST.

    Thank you

    1. Hi Kathy, thanks for reading and good question. Different systems have different characteristics of how the regen cycle works. Yours might be demand-initiated so that you may notice a “typical” time, but then with different water usage patterns in your household the timing can change. It could also just be a timer that has some kind of variable. The best way to know is to consult your system’s instruction manual or contact the manufacturer.

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