Regeneration is an essential part of water softener operation. When a softener performs a regeneration cycle, it flushes the resin beads, removing the built-up calcium and magnesium ions, and replenishes the resin with a fresh batch of sodium ions.
Without regeneration, a water softener wouldn’t be able to soften your water – it’s as simple as that. But how does the regeneration process actually work? And why does it take so long?
In this guide, I’m sharing the 5 stages of water softener regeneration. By the end, you’ll understand exactly what goes into this process, and just how thorough it needs to be.
Table of Contents
1️⃣: Brine Tank Fill
In the first stage of water softener regeneration, water is directed into the brine tank, where it fills to just below the salt level. Water is needed to create brine, a silky combination of dissolved salt and water.
Next up, before the resin beads can be replenished, the tank must be flushed in a process called backwashing. The resin bed can accumulate debris, dirt, impurities, and fragmented beads, which all must be removed to keep the water softener system operating efficiently.
During this stage of regeneration, water is sent into the bottom of the resin tank. It is then sent upward through the resin beads, washing away contaminants and suspended solids.
Next, water leaves the resin tank through the top, keeping hold of any minerals and debris it has picked up along the way. After leaving the tank, this contaminated water washes down the drain.
Typically, this stage of regeneration will take between 10 and 15 minutes, and works at a flow rate of between 4 and 8 GPM. It’s important that flow rate isn’t too high here, or it could result in the loss of resin.
This cycle gives the water softener resin up to 50% more space, preparing it for the brine draw stage.
3️⃣: Resin Tank Brine Draw
In the next stage of the regeneration cycle, the system draws brine from the brine tank into the resin bed. When the brine solution interacts with the resin beads, it triggers a process known as reverse ion exchange – where the sodium ions are exchanged with the hardness minerals in the resin bed.
A flow rate of around .05 to 1 GPM is needed for this brine draw process. Depending on the brand and the model, the brine flow in your system may be upward or downward. It doesn’t make much of a difference either way, though upflow tends to be the more efficient cycle.
This process takes about half an hour, and eventually results in all hard water minerals being replaced with sodium in the resin tank. The system is now ready to provide soft water treatment – but the regeneration cycle hasn’t finished yet.
4️⃣: Brine Rinse
At the end of the brine draw, water is sent into the resin tank to rinse the resin. Again, this is a slow process at a flow rate of around 0.5 to 1.0 GPM, enabling the reverse ion exchange process to be absolute.
Any lingering brine is removed from the resin bed at this rate and washed down a drain. In all, this cycle takes around 20 minutes from start to finish.
5️⃣: Fast Rinse
Finally, the fast rinse cycle sends water at high speeds through the resin bed, typically traveling from the top of the resin to the bottom.
Any hard water minerals and remaining brine will be removed by this water softener regeneration stage.
During the fast rinse cycle, the resin bed becomes compacted, ready to produce softened water. This is the longest cycle, taking up to 50 minutes from start to finish. A flow rate of 1.5 to 2 GPM is needed to rinse the resin.
❔ Quick-Fire FAQs
How often should my water softener regenerate?
It depends on your water usage and the hard water problem you’re dealing with. Most water softeners will regenerate every two to three days at around 3 am, to prevent interruptions to water usage during the day.
What if my water softener isn’t regenerating?
You may be dealing with one of many issues, including a clogged brine line, a blocked drain line, or a clogged injector/venturi. Check that brine can be drawn between the two tanks. If not, you’ve probably got a blockage somewhere.
Why is my water softener stuck in regeneration?
Again, if your water softener is stuck in a regeneration cycle, you’re most likely dealing with a brine issue. Check your valves and lines for blockages and fix the problem ASAP.
How much water do water softeners need to regenerate?
Most water softeners require three times the volume of concentrated brine to regenerate. The majority of modern water softeners are very efficient, and use around 2% of the volume of soft water produced between regeneration cycles.
How can I tell if my water softener is regenerating?
You’ll usually be able to hear a low motor hum or the sound of trickling water. Most water softeners are set up to regenerate overnight, so unless you stay up especially for the occasion, you probably won’t be aware that your water softener is regenerating at all.
👉 In the market to purchase a system? See this guide for my top picks of the best systems in 2023
Learn more about the ion exchange process in my full detailed post here.