Guide to Water Softener Cleaning & Sanitizing:

This article provides an owner's guide to water softener cleaning, and sanitizing - two steps in keeping a water conditioner working properly.

We discuss the use of various chemicals & cleaners to sanitize or clean out water softeners and their brine tanks, and we comment on the effect of such chemicals on septic systems.

We discuss the formation of salt crust in the brine tank, the accumulation of dirt & debris in the brine tank, & how to remove these problems & contaminants in a water conditioner

. We also discuss using iron removing products or other chemicals to clean & sanitize a water softener.

How to Sanitize a Water Softener or Water Conditioner

This procedure gives step-by-step details of how to disinfect or "sanitize" the resin tank and also the bottom of an in-use brine tank without removing the salt.

Our focus here is on resin tank disinfection or sanitizing. The resin tank is where the actual water softening takes place.

Sanitizing is necessary because the simple salt or brine backwash cycle does not remove microorganisms like bacteria or algae that like to grow in the resin bed or sometimes in the brine tank.

Our sketch illustrates the brine tank (at left) and the water softener resin tank (at right) in the drawing.

The brine tank or salt tank is the separate container (into which you add salt) used to produce brine that is in turn used to recharge the salt, i.e. to regenerate the resin tank.

The resin tank is where the actual water softening takes place.

How Often / When Should a Water Softener be Sanitized?

1. If your water softener has been shut down for a week or more, if you are restoring to service a building that has been winterized
   
   For help winterizing
   
   see WINTERIZE WATER SOFTENER


2. If you suspect bacterial contamination: if your building water supply both hot and cold water have a stinky sulphur smell or "rotten egg" smell (caused by harmless but nasty smelling sulfate-reducing bacteria)
   
   Or if you see a color change in water after it has run through the water softener
   
   
   Or if the water tastes foul after it has run through the water softener
   
   
   Or if a water bacteria test indicates that your water supply is contaminated.
   
   Also see BACTERIA LEVELS in WATER, INTERPRETATION
   
   If only the hot water supply in the building smells like rotten eggs,
   
   see ANODES & DIP TUBES on WATER HEATERS.
3. If work on the water softener exposed the control valve body internal parts to air
4. If new resin has just been installed in the water softener resin tank
5. According to your water softener's maintenance schedule. Manufacturers recommend cleaning and sanitation intervals ranging from as often as every three months to annually.
   
   Frankly I have never encountered a homeowner who sanitizes their softener every three months but perhaps some do.

All salt used in water softeners, whether it is "rock salt", "salt pellets", "solar salt" or "evaporated salt" is a natural mineral that will contain impurities and possibly soil particles. These materials accumulate in the bottom of the salt tank during normal use and eventually can interfere with water softener operation or water quality.

For a complete water softener cleanout, every year or two we let the water softener use up its salt so that we can inspect and remove any dirt or sludge that may have accumulated at the bottom of the salt tank.

The following procedures are given in both basic and detailed forms and are adapted from maintenance recommendations from Culligan™ and other water conditioner companies.

If you need to clean a dirty salt tank or brine tank, see this separate

topic:SOFTENER BRINE TANK CLEAN & DISNIFECT

7 Easy Steps To Disinfect or Sanitize a Water Softener Resin Tank

What follows is a detailed description of a typical procedure. But details for your softener may vary. So be sure to read the instructions for cleaning your specific water softener brand and model - described in the owner's manual or service manual for your water softener.

1. Turn off any other water treatment equipment that uses Sodium hydrosulfite, Sodium bisulfite, or any other reducing agent and disconnect that device temporarily.
   
   If you're not sure what your other water treatment equipment is, ask your plumber or water treatment company who installed it.
   
   If you are not the original owner of the building and don't know who installed your equipment, look on the equipment for its name, model number, and for a sticker that may identify the local installer.
   
   
2. Run a normal "extra" or manual regeneration cycle to flush out the equipment;
   
   
3. If the salt tank is completely empty put 3 gallons of water into the salt tank.
   
   If you are sanitizing an "in-use" water softener there will be both salt in the brine tank and at some water in the bottom of the tank.
   
   In this case Skip step 3 and go directly to step 4.
   
   In a more-extensive brine-tank cleanout you will have removed all salt from the brine tank and have cleaned it of any visible mud, crud, or debris (also using dish soap and a dilute bleach solution that is dumped out of the brine tank and the tank is then flushed with clean water), and you've checked that the brine tank float tube is also clean and that the float moves freely.
   
   This is the most thorough cleaning approach. However some water softener manuals (such as the Sears Kenmore 100 / 150 UltraSoft) note that you can perform this sanitizing cycle with or without salt in the brine tank.

4. Add bleach to the brine tank:
   
   Bleach dosage to sanitize a water softener
   
   Use 1.2 fluid ounces (a bit over 2 tablespoons) of bleach per cubic foot of resin in the resin tank.
   
   Note that the volume of resin in the tank is always less than the total physical volume of the tank itself.
   
   2 Tbsp = 1 ounce of liquid (1 US Tbsp = 0.5 US Fluid ounces)
   
   1/4 cup = 2 ounces of liquid
   
   Small water softeners: 1-2 ounces of bleach
   
   A typical home water softener is 2-3 cubic feet and gets 1-2 ounces or about 1/4 cup of bleach.
   
   For a Sears Kenmore 100-150 series water softener (others are similar) the company suggests adding 3/4 ounce or 1-2 tablespoons of 5.25% unscented household bleach to the water in the brine tank.
   
   Larger water softeners: 4-5 ounces of bleach
   
   For a larger resin tank of around 4 cubic feet of volume use 4 to 5 fluid ounces of liquid bleach - that's 1/2 a cup or about 8 tablespoons of household bleach (5% bleach) or just 2 ounces if you are using industrial strength (10-15% concentration) bleach.
   
   Note 1 below shows how to calculate the volume of your water softener resin tank.
   
   Examples of "Household bleach" brands include BoPeep bleach, Clorox bleach, Eagle bleach, Linco bleach and White Sail bleach.
   
   Add the bleach solution directly to the brine well (topmost red arrow in our photo above) in the salt tank.
   
   (The bleach quantity needed to sanitize the water softener is discussed immediately below).

Watch out: do not pour bleach right onto the salt in the salt tank as it may not dissolve uniformly into the brine.

Be sure to pour the bleach into the brine well where you'll see liquid brine not onto the salt. You will need to remove the small cap over the brine float tube. Try to pour the bleach down the center of the tube.



After inserting the bleach use a cup or two of clean water to wash bleach off of plastic parts that are not submerged in water at the bottom of the brine well.

Watch out: do not overdose with bleach or you may damage the resin in the resin tank. Using a quantity or concentration of bleach higher than recommended by your water softener manufacturer OR leaving the resin exposed to a strong bleach solution for more than an hour risks damage to the resin.

Note 1: How to calculate the volume of the resin tank & the quantity of bleach needed

For a larger water softener such as the Vertex 5800MEDS (using a Fleck 5800 LXT control head) whose resin tank measures 13" diameter x 54" high we calculate the amount of bleach needed as follows:

Volume V = 1/2d (diameter)² x pi (3.1416) x h (height)

where all units are in the same measurement such as inches and where 1/2 the diameter d of a circle = its radius.

(1/2 x 13")² x 3.1416 x 54" = 7170 (rounded up from 7167) cubic inches or about 4.1 cubic feet.

(1.2 oz. bleach / cubic ft.) x 4 cubic feet = 4.8 ounces of bleach or about 8 tablespoons (TBSP) of bleach.

More about calculating volume of a cylinder is

at VOLUME of WATER IN a CYLINDER - CALCULATION

Note 2: bleach concentration recommendations for water softener resin tank sanitation

In sanitizing a water softener resin tank using bleach (5% sodium hypochlorite or household bleach, un-scented liquid) the objective is to get a bleach concentration (5% household bleach or sodium hypochlorite) of 50 to 100 ppm.

In cases of serious contamination of the resin tank you can use higher concentrations of bleach up to 500 ppm, but

Watch out: Other web articles we have seen give directions use much more bleach, suggesting that you pour a one cup of household bleach (if your water softener is a 9" diameter unit) or two cups of bleach (if your water softener is a 12-inch diameter unit) right into the salt tank.

Don't do that unless your brine tank salt level is very low. If the level of salt in the brine tank is low enough that you see a liquid / salt crystal or tablet slurry that you can stir with a paddle, then you can dump the bleach right into the slurry and mix it up.

But if the salt level in the tank is high, we warn that if you soak a salt tank full of salt with bleach you will never be able to flush out all of that bleach unless you remove all of the bleach-contaminated salt.

A result is that you may overdose the resin in the resin tank, and you may have a devil of a time flushing the bleach out as well. Your water will continue to smell like bleach after future regen cycles.

Note 3: Alternatives to Bleach for sanitizing a water softener

For sanitizing water softeners other chemicals sometimes used include special sanitizing packs provided by your softener manufacturer, potassium permanganate ("green sand" used in some exchange-type water softeners), iodine, and other oxidizers, but as we will comment below, some of these are dangerous.

Some water softener manufacturers such as Culligan provide their own sanitation treatment chemicals.

Culligan provides a 0.5 oz. Sani-System pack. To use a Culligan Sani-System pack you simply dump the contents of one package into the brine tank periodically, or you have the sanitation package installed by your water softener salt delivery service.

Hydrogen peroxide can be used to sanitize a water softener resin tank if you keep the concentration low - around 1% - provided your water supply and piping are not iron contaminated -

Watch out: when using hydrogen peroxide: you risk a dangerous, even fatal hydrogen explosion.

Frankly unless you're an expert we recommend staying away from hydrogen peroxide for water softener sanitation.

More details are

at WATER SOFTENER RESINS & CLEANING COMPOUNDS

5. Run the water softener through a normal or manual regeneration cycle.
   
   This will cycle the bleach-solution out of the brine tank and through the resin tank.
   
   An hour of contact time - a typical regen cycle time on many softeners - is enough for the bleach solution to be effective if you used the recommended bleach strength and quantity for your softener.

If your softener's regen cycle time is much shorter than an hour of backwash you can alternatively stop the backwash / regen cycle while the resin tank is saturated with bleach solution and let it sit long enough that the total exposure time is about an hour.

Watch out: exposing the water softener resin to high concentrations of bleach (more than 500 ppm) or to any bleach for longer periods (more than an hour) may damage the resin and require resin replacement.

Don't do that.

Watch out: also, using more bleach is a more aggressive sanitizing process that may require extra regen cycles to flush all of the bleach out of the system

6. Run an extra manual water softener recharge cycle: set the water softener to perform an extra (manual) recharge cycle.
   
   The control to run an extra regen cycle varies by water softener brand or model.
   
   On the Sears Kenmore 100 / 150 series water softeners that use an electronic control head you'll have to press and hold the ON/OFF-HOLD button for three or more seconds to start a recharge / regen cycle.
   
   The regeneration cycle may take about two hours.
   
   This will flush salty chlorine disinfectant through the equipment. (No, using the recommended quantity of bleach will not harm the septic system.)
   
   
7. Add salt? If you performed sanitizing of the water softener with no salt (or potassium chloride KCl) in the brine tank remember to now re-fill the salt tank with your salt supply.
   

   Watch out: as we explain
   
   at WATER SOFTENER SALT SUBSTIUTE: POTASSIUM CHLORIDE, different water softener settings will be required if you're using KCl.
   

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Reader Q&A - also see RECOMMENDED ARTICLES & FAQs

On 2020-11-30 by Anonymous

Ok thanks again!

On 2020-11-30 by (mod) - are metal shards that fell into the well going to contaminate our water?

Probably not, but NOONE can say based on so little data. Chemicals. Drilling oil. Groundwater leaks, bacteria, etc. You should contact a locsl water test lab to set up a testing program,
And
Use the on page search box to find and read the warnings at our article

OTHER PEOPLE'S MONEY

On 2020-11-30 by Anonymous

Thanks for the input.Sorry if this is a duplicate message, not sure if my last one went through. Would it be expected that the shards of metal, such as the ones that likely had fallen into the well, would leach harmful metals into the drinking water to the point of any significance?

On 2020-11-30 - by (mod) - ok to drill the well casing top to secure the top cap to the casing?

Gee: like the Poughkeepsie Police told Anna Bannana when she called to ask them to tell Metro North to stop blowing their train horns at night, "Well that's one I've never heard before"

But "never heard before" doesn't mean the plumber's wrong- I just don't know exactly what he's doing. If the well head is water tight it may be fine.

Yeah dropping debris into the well is not the best, but it happens; falls to the bottom, and if the pump is sufficiently off the bottom (and screened) so as not to pick up metal shavings then the drill shards shouldn't damage the pump;

On 2020-11-30 by Anonymous

Oh boy, got another well water question. Just got off the phone with a plumber at the vacation house who said that he instead of installing a water tight well cap on the well casing as I had asked. He had retrofitted the existing well casing to be weathertight.

To do this, he said that he drills all the way into the well casing and put screws connecting the welcome to the well casing. I don’t know too much about Wells, but my first thought was whether or not the drilling into the well casing like that puts little bits of ometals right into the well water supply.

With this be expected to cause any problems with well water or would the impact likely be so minimal as to be forgettable? I apologize if my question reflects limited understanding of Wells and how they work, but I wanted to ask. Thank you

On 2020-11-29 - by (mod) - if you don't need to sanitize the water softener it's better to put it in bypass when shocking the well

Yes I think if you don't need to sanitize the water softener it's better to put it in bypass. You may also find that if you use too much bleach in your well you'll have a hard time getting it out of other equipment like pressure tanks and water heaters

Use the article index to find out article on

well shock procedure

to see proper procedure details

On 2020-11-29 by Anonymous

I am doing the manual regeneration of the water softener system now. Going forward, is it best that I put the water softener system in bypass if I have to bleach shock my well again?

Last time I shocked well, I did not put it in bypass mode and ran the water through house garden hose spigot until I could smell bleach and then ran briefly in indoor faucets so that the bleach water could sit in plumbing for 24 hours. Thank you

On 2020-11-25 by Anonymous

Thank you very much again!

On 2020-11-24 - by (mod) - does using bleach in a water softener form cancer-causing carcinogens?

Anon: please find your question about using bleach to sanitize a water softener (it's ok at proper concentration) and our detailed reply now at

WATER SOFTENER RESINS & CLEANING COMPOUNDS

On 2020-11-24 by Anonymous said:

RE-Posting:

Anonymous said:

no sir, proud to say I’m not drinking bleach here.

Where I saw the info about bleach mixing with water softener beads making a resin that is carcinogenic was a website called water tech online. I have no idea how accurate or inaccurate accurate that information is, but I wanted to ask. I’m going to try to add the link here if you wanted to take a look. watertechonline [dot] com/home/article/15530067/protect-the-resin

What I did was shock my well with chlorine bleach. I did not do anything with the water softener at all. I used more bleach than needed as it turned out and it took a good hour of running the water for the bleach smell to leave. I will do the manual regeneration of the water softener tank to be safe that all is flushed out of there as well.

(mod) said:

I will look at that like and do some research and report back here but I am not sure that we actually have an issue here. It's certainly common for water softener manufacturers to describe procedures for sanitizing the system using bleach

Anonymous said:

Thank you again for your time and expertise. I’ll check back to see if you find anything.

On 2020-10-30 by (mod) - how to get the bleach out of the brine tank & is it OK to use bleach to sanitize a water softener resin tank?

Anon: please find your question and our detailed reply now at

WATER SOFTENER RESINS & CLEANING COMPOUNDS

On 2020-10-28 by Anonymous

I have recently shocked my well using bleach. As it turned out, I ended up using probably about 4X amount of bleach then was actually required for the size of my well.

I applied the bleach using buckets of water to dilute the bleach.

I read afterwards that allowing any bleach to sit in water softener can damage it. I’m not sure how all of this works, but can you tell me if there’s reason to think I may have damaged the softener?

On 2020-10-21 - by (mod) - water softener resin beads are not toxic

Janet, thanks for asking a helpful question:

Are water softener resin beads harmful or toxic?

These are tiny beads of resin - pretty inert; As our drinking water passes over them we'd not expect a toxicity issue.

Water softener resin beads are not toxic.

See this Purolite WATER SOFTENER RESIN SAFETY DATA SHEET [PDF] https://inspectapedia.com/plumbing/Water-Softener-Resin-MSDS-Purolite.pdf

that states "The mixture does not meet the criteria for classification." [as a hazard]

Watch out: that does not mean it's ok to eat resin beads nor to get them into your lungs nor in your eye. Any small particles can be harmful even if the particle is inert.

As experts say, "the dose makes the poison". If you ingested a sufficient quantity of water softener beads or any other small pellet that could be a serious health hazard.

On 2020-10-21 by Janet - will softener resin harm you?

can the resin in the software harm you if you get it inside your body excuse me that is softener

On 2019-06-17 - by (mod) - how much bleach to use in the water softener

Thank you Lehi we'll edit the article for clarity. I appreciate that you took time to write.

On 2019-06-17 by lehiatt@cox.net

In item 4 of the 7 steps to sanitize a softener resin tank, you state to us 1.2 oz of household bleach per cubic ft of resin...or "1+ tablespoons per oz". That disagrees with further down using 2 tbsp for 4 lbs of resin. The second case is correct...2tbsp per oz of bleach to treat 4 cubic ft of resin.

@lehiatt@cox.net,
meant 8tbsp per 4cuft of resin.

...

Continue reading  at WATER SOFTENER RESINS & CLEANING COMPOUNDS or select a topic from the closely-related articles below, or see the complete ARTICLE INDEX.

Or see these

Recommended Articles

• WATER CONDITIONER / SOFTENER MANUALS
• WATER SOFTENER CLEANING & SANITIZING
  • BRINE TANK BRIDGING or CRUSTING
  • DIRT & DEBRIS in BRINE TANK
  • SOFTENER BRINE TANK CLEAN & DISNIFECT
  • SOFTENER RESIN TANK SANITIZE / DISINFECT
  • SANITIZE NEW WATER SOFTENER
  • WATER SOFTENER IRON & SEDIMENT REMOVAL
  • WATER SOFTENER RESINS & CLEANING COMPOUNDS
  • WATER SOFTENER SANITIZER IMPACT on SEPTICS
• WATER SOFTENER OPERATING CYCLES
• WATER SOFTENER MANUAL REGENERATION
• WATER SOFTENER / TREATMENT TURN-ON - returning a water softener to service
• WATER STAINING CONTAMINANTS
• WATER TREATMENT EQUIPMENT DISINFECTION

Suggested citation for this web page

SOFTENER RESIN TANK SANITIZE / DISINFECT at InspectApedia.com - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.

Or see this

INDEX to RELATED ARTICLES: ARTICLE INDEX to WATER TREATMENT SYSTEMS

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