Water Softener Regeneration: How Often, How Long and Best Settings
Quick answer: regeneration (also called a recharge) is when a softener rinses its resin with salty brine to restore its softening power. It takes from about 30 minutes to 2 hours depending on the model, and Whirlpool, Rheem and Fleck softeners all default to starting it at 2:00 a.m. How often depends on three things: your softener’s capacity, your water’s hardness and how much water you use. Divide the capacity by the hardness to get the gallons between regenerations, then divide by your daily use. A well-sized softener regenerates about once a week. Fleck valves also force one every 14 days by default, and Whirlpool and Rheem let you set a maximum of up to 15 days. The calculator below runs the numbers for your home.
What happens during a regeneration cycle
As the softener works, its resin beads fill up with calcium and magnesium. Regeneration flushes them back out with brine from the salt tank and reloads the beads with sodium. See how a water softener works for diagrams. On a Fleck 5600SXT, a common valve on do-it-yourself softeners, a regeneration runs these steps:
| Step | What happens | Default time |
|---|---|---|
| 1. Backwash | Water flows up through the resin to loosen and clean the bed, then goes to the drain | 10 minutes |
| 2. Brine draw and slow rinse | Brine from the salt tank passes slowly through the resin, swapping the hardness for sodium, then a slow rinse follows | 60 minutes |
| 3. Rapid rinse | A fast rinse flushes out the leftover brine | 12 minutes |
| 4. Brine refill | Water refills the salt tank to make brine for next time | Set by softener size |
Default times from Quality Water For Less’s Fleck 5600SXT programming guide.
Brands run the same steps in different orders. Whirlpool’s softeners, for example, refill the salt tank first, then draw brine, backwash and fast rinse. Whirlpool also offers optional extra backwash cycles: one to clean the resin on water with clear-water iron, and one to keep its cleansing screen clear. Every step except the refill sends water down the drain.
How long does water softener regeneration take?
| Softener | Regeneration time | Water used |
|---|---|---|
| A. O. Smith AO-WH-SOFT-350C | 27.5 minutes (efficiency setting) to 33 minutes (capacity setting) | 21–25 gallons |
| Fleck 5600SXT (default settings) | About 1.5 hours: 82 minutes plus the brine refill | Depends on tank size and flow controls |
| Rheem RHS18 | About 2 hours | Up to 26.4 gallons at the highest salt setting |
| Whirlpool WHES48 | About 2 hours | Up to 44.2 gallons at the highest salt setting |
From A. O. Smith’s, Rheem’s and Whirlpool’s manuals and the Fleck programming guide.
So most regenerations take between half an hour and two hours. Bigger softeners and higher salt settings take longer and use more water.
How often should a water softener regenerate?
A metered softener regenerates when it has softened as many gallons as its capacity allows. Pentair’s manual for the Fleck SXT control explains the math: the capacity in grains, divided by your water’s hardness in grains per gallon, minus a reserve. Then divide by how much water you use each day:
- Gallons between regenerations = capacity ÷ hardness, minus the reserve
- Days between regenerations = those gallons ÷ your daily water use
Example: a softener set to 32,000 grains on 15 gpg water can soften about 2,133 gallons. Keep back a 15% reserve, as the Fleck guide does, and that’s about 1,813 gallons. A household of three using 75 gallons each a day uses 225 gallons a day, so the softener regenerates about every 8 days.
About once a week is a sensible target; it’s what our size calculator aims for. Controls can also set a maximum: the Fleck guide’s day override is 14 days, and Whirlpool lets you choose anywhere from 1 to 15 days. On water with clear-water iron, Whirlpool suggests regenerating every few days to keep the resin clean.
Water softener regeneration calculator
Enter your softener’s capacity setting and your water details to see how often it should regenerate.
Enter your softener’s details to see how often it regenerates.
How it works: capacity ÷ hardness × (1 − reserve) gives the gallons between regenerations, following Pentair’s formula for the Fleck SXT control. Daily use is people × gallons per person. Whirlpool and Rheem softeners work out their own timing from your hardness setting and water use, so treat the result as an estimate for those.
Demand vs timer regeneration
How a softener decides when to regenerate matters as much as how often. Pentair’s Fleck SXT manual describes the main control types:
| Control type | When it regenerates |
|---|---|
| Meter immediate | As soon as the metered capacity runs out, at any time of day |
| Meter delayed | At the set regeneration time (such as 2:00 a.m.) after the capacity runs out; a reserve covers the water used before then |
| Time clock | Every set number of days, whatever water you’ve used |
| Day of the week | On the days you switch on, at the set time |
From Pentair’s Fleck SXT control manual. Metered controls also regenerate when the day override is reached.
Metered regeneration, also called demand-initiated regeneration, only uses salt and water when you’ve actually used the softener’s capacity. It’s one of the requirements for an NSF/ANSI 44 efficiency rating, according to the Department of Energy’s Building America Solution Center. A timer regenerates on schedule even when you’re away, and can run short when you have guests. If you’re choosing a softener, see our high-efficiency softeners.
The best time to regenerate
Whirlpool, Rheem and the Fleck guide all default to 2:00 a.m., and Whirlpool says that’s a good time for most households because water isn’t in use. Rheem’s manual explains why it matters: if you draw water during a regeneration, hard water bypasses the softener. Whirlpool adds that using hot water during a regeneration refills the water heater with hard water. If someone in your home showers at 2:00 a.m., move the time; our settings guide shows where. A twin-tank softener avoids the problem altogether, because one tank stays in service while the other regenerates; see dual-tank softeners.
How to regenerate a water softener manually
A manual regeneration is worth running if you’ve used much more water than usual, after the softener ran out of salt (add salt first, Rheem says), or after cleaning the softener.
Whirlpool and Rheem
- Now: press and hold the RECHARGE button for 3 seconds until “RECHARGE NOW” (Rheem) or “RECHARGE” (Whirlpool) flashes. Rheem says it takes about 2 hours.
- Tonight: press and release RECHARGE once to schedule an extra regeneration at the next set time, usually 2:00 a.m.
Fleck 5600SXT
- Tonight: press the Extra Cycle button once. The service icon flashes to show a regeneration is queued for the set time; press it again to cancel.
- Now: press and hold the Extra Cycle button for 5 seconds.
- During a regeneration: pressing Extra Cycle skips to the next step, so avoid it unless you mean to.
Some guides and sellers label the Fleck button “REGEN”; it’s the same button.
How to tell if your water softener is regenerating
- The display changes. Whirlpool shows the time left in the regeneration during every cycle except the refill. A Fleck SXT shows the current step and counts down the time left in it.
- Water runs to the drain. You may hear water flowing in the drain line. Whirlpool describes a slow flow during the brine step and a fast flow during backwash and rinse.
- The brine level drops. Shine a flashlight into the brinewell; Whirlpool says the liquid level should drop noticeably during the brine step, which can take 15 to 20 minutes.
How much water and salt does regeneration use?
The softeners above use about 21 to 44 gallons per regeneration. For an NSF/ANSI 44 efficiency rating, a softener must use no more than 5 gallons of water per 1,000 grains of hardness removed; Whirlpool’s and Rheem’s efficiency-rated softeners use 3.0 gallons per 1,000 grains at their lowest salt setting. Salt per regeneration ranges from under 2 lb to over 20 lb depending on the size and setting. Lower salt settings remove more hardness per pound, as the Fleck chart in our settings guide shows.
Where the regeneration water goes
Into a drain: Whirlpool and Rheem list a floor drain, laundry tub, sump or standpipe, with a 1½-inch air gap between the hose and the drain to stop backflow. A. O. Smith asks for a 2-inch air gap. NDSU Extension warns that regeneration water can overload or reduce the effectiveness of small septic or sewer systems, and some California communities restrict softener discharge; see our salt-free guide. Check your local plumbing code, and see how to install a water softener.
Water softener not regenerating?
- No power. Whirlpool says the softener won’t regenerate while the power is out. Pentair adds that the Fleck SXT doesn’t count water used during a power failure.
- Wrong time of day. After a long outage the clock may be wrong, so regenerations happen at odd hours. Reset it if it’s flashing.
- It regenerates but the water stays hard. Check the salt, look for a salt bridge, and make sure the bypass valve is in service.
- It regenerates too often or not often enough. Check the hardness setting; a wrong one makes the softener regenerate too early or too late.
- The salt tank fills with water. The softener isn’t drawing brine, usually because of a plugged nozzle and venturi.
Our “is my softener working?” checker walks through these in order.
Frequently asked questions
Can you use water while the softener is regenerating?
Yes, but it won’t be soft: Rheem says hard water bypasses the softener during regeneration. Avoid using hot water, which refills the water heater with hard water, Whirlpool says.
After how many gallons should a water softener regenerate?
Divide the capacity by your hardness, then take off a reserve. A 32,000-grain setting on 15 gpg water allows about 2,133 gallons, or about 1,813 with a 15% reserve.
Is it bad if my softener regenerates every night?
Not harmful, but it suggests the softener is small for your home, the hardness setting is too high, or a leak is using water. Check the setting, then use the calculator above or our size calculator.
What does recharge mean on a water softener?
The same as regeneration. Whirlpool and Rheem call it a recharge; Fleck calls it a regeneration.
How do I set the regeneration time?
On Whirlpool and Rheem softeners it’s the “RECHARGE TIME” screen, after the hardness setting. On a Fleck 5600SXT it’s the “RT” setting in master programming. Our settings guide walks through each.
Related guides
- How to set your water softener’s hardness
- What size water softener do I need? (calculator)
- Best high-efficiency water softeners
- How does a water softener work?
Sources
- Pentair, Fleck SXT control manual: control types, capacity formula, manual regeneration and power failures.
- Quality Water For Less, Fleck 5600SXT programming guide: cycle times, reserve, day override and regeneration time.
- Whirlpool, WHES48 installation and operation manual (2023).
- Rheem, RHS18 installation and operation manual (rev. G, 2025).
- A. O. Smith, AO-WH-SOFT-350C owner’s manual: regeneration time and water use, drain air gap.
- U.S. Department of Energy, Building America Solution Center, Water Softeners: NSF/ANSI 44 efficiency rating criteria.
- NDSU Extension, Water Softening (Ion Exchange), WQ1031 (revised May 2022): septic and sewer systems.