Bleach Shortage? Here’s How to Make Bleach from Pool Shock (and How to Purify Water With It)

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We’ve all seen photos of the empty shelves in stores across American, and one thing that has become increasingly difficult to find is bleach.

Typically, a bottle of bleach should contain between 6 and 8.25% sodium hypochlorite, a more dilute solution that one might expect, similar to an item such as peroxide. Unfortunately for people stockpiling bleach, the potency of your product may diminish fairly rapidly over time. The dilute solution of bleach held by many people could decrease in potency as much as 20% in one year, and that’s if it was stored in “perfect” conditions of at or below room temperature.

Not only is bleach important for cleaning during an outbreak of pandemic illness, but it can also be used to purify water.

You can make your own bleach with pool shock.

The good news is, you can make your own bleach with granular calcium hypochlorite, the primary component of typical pool shock. It’s essential to confirm that your pool shock is not contaminated by other chemicals, such as algicides. Only HTH is acceptable for purifying your water.

In other words, it’s a different chemical composition of bleach. The granular form of calcium hypochlorite can be used to substitute your typical bleach, sodium hypochlorite, in killing pathogens to purify water (not to remove chemical, non-biological toxins, of course).

A forum post that quotes an EPA website says that a 5 lb bottle of pool shock can produce around 649 gallons of “stock chlorine,” something resembling about 649 gallons of bleach. Every single gallon of stock chlorine is capable of disinfecting around 200 gallons of water. So, if 640 gallons of that are possible to produce with simple water and a 5 lb bottle of pool shock, that seems extremely useful.

Make bleach with pool shock.

For an easily understood equation, here’s something people can do.

The EPA recommends that your household bleach be used at a ratio of 8 drops per gallon of water to purify water, noting that the product must be free of adulterants essentially, or in their words, only products suitable for sanitization as shown on the label.

For use of pool shock, the ratio to purify water is around 1 part “chlorine solution” to 100 parts water.

First, take a heaping teaspoon, not tablespoon, of granular calcium hypochlorite and dissolve it in 2 gallons (8 liters) of water.

DO NOT DRINK THIS: this is the recipe for a “chlorine solution,” used at that ratio of 1 part chlorine solution to 100 parts water. This is your bleach. It can be used for cleaning or water purification.

How to purify water with bleach

It may seem strange or dangerous to prepare a solution like this and then add it to water you obtained from a creek, lake, river, or wherever else it’s obtained. However, once you get used to the concept and the bulletproof nature of the science, the strangeness will subside. Just as long as one utilizes the pure, proper form of granulated calcium hypochlorite, nothing scented or adulterated, it should work fine.

Chemicals that are harmful to the body, such as mercury, PCB’s or whatever else, may happen to be in the water of certain lakes, streams, or wherever you search, although certainly nowhere near every source of water is contaminated. One crucial layer of protection from contaminants in water can be added by the use of cheap, readily available granulated calcium hypochlorite.

Purification with bleach is a very simple process.

Once the teaspoon of pool shock has dissolved in the 2 gallons of water, you can mix it into the water you want to purify at the ratio of 1 part makeshift-chlorine to 100 parts water.

Before drinking the final batch of water, be sure to let the chlorine-water solution sit for at least 30 minutes before drinking. The pathogens you’re trying to kill take just about that long to become harmless.

Here are the instructions straight from the EPA website:

Disinfect water using household bleach, if you can’t boil water. Only use regular, unscented chlorine bleach products that are suitable for disinfection and sanitization as indicated on the label. The label may say that the active ingredient contains 6 or 8.25% of sodium hypochlorite. Do not use scented, color safe, or bleaches with added cleaners. If water is cloudy, let it settle and filter it through a clean cloth, paper towel, or coffee filter.

    • Locate a clean dropper from your medicine cabinet or emergency supply kit.
    • Locate a fresh liquid chlorine bleach or liquid chlorine bleach that is stored at room temperatures for less than one year.
    • Use the table below as a guide to decide the amount of bleach you should add to the water, for example, 8 drops of 6% bleach, or 6 drops of 8.25% bleach, to each gallon of water. Double the amount of bleach if the water is cloudy, colored, or very cold.
    • Stir and let stand for 30 minutes. The water should have a slight chlorine odor. If it doesn’t, repeat the dosage and let stand for another 15 minutes before use.
    • If the chlorine taste is too strong, pour the water from one clean container to another and let it stand for a few hours before use. (source)
Volume of Water Amount of 6% Bleach to Add* Amount of 8.25% Bleach to Add*
1 quart/liter 2 drops 2 drops
1 gallon 8 drops 6 drops
2 gallons 16 drops (1/4 tsp) 12 drops (1/8 teaspoon)
4 gallons 1/3 teaspoon 1/4 teaspoon
8 gallons 2/3 teaspoon 1/2 teaspoon

*Bleach may contain 6 or 8.25% sodium hypochlorite.

Some of the benefits of using pool shock

The benefit of purifying water with granular calcium hypochlorite is that the solution of “chlorine” made with 1 teaspoon to 2 gallons, can be used for small batches of purified water, and that’s all that is needed at the time.

Bleach or makeshift chlorine solution both degrade and go bad fairly quickly, so if this is kept in granular form, it’s only necessary to make small batches at a time that won’t degrade and go to waste. You can store pool shock to make hundreds of gallons of bleach in a tiny area compared to the space you’d need to store a similar quantity of bleach.

You can find pool shock in a variety of places: any place that sells pools or jacuzzis will have it on hand. Even discount stores like Walmart will have pool shock during swimming pool season. You can also find it on Amazon for less than $20.

Even if you have plenty of bleach on hand, it never hurts to have some long-lasting pool shock in your emergency supplies.

About Cassius

Cassius K is a writer from North Highlands, California.

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  • THIS is an awesome article thanks Cassius!!

    Here is what my husband suggested we do for now because we live in a super small town not much infrastructure, utilities sketchy at best but we have a Brita water filter and for now we are pouring that water into a pitcher to use for teeth brushing etc. We filled up 2 pitchers and just keep the system going. It’s just a safety afterthought just in case our water system isn’t treated.
    Keep these great articles coming!!

  • There are different strengths of pool shock…4, I think. My Wal-Mart had only a level 3. The recipe is a little different depending on the content.

  • I’ve read that not all pool shock is the same. That you need to purchase pool shock that only contains the main active ingredient, calcium hypochlorite. Is there any way to tell which pool shock is the best for use in this way? What additives should we be on the lookout that indicate a specific pool shock is not a good one to use in this way?

  • I am unable to buy anything online since my bank account is empty. Traveling over 100 miles to a city with any decent store right now is out of the question. I talked with Lee our butcher who is up in Mertzon, Texas. He said the Mertzon bank closed and were not going to put any tellers in to work. Are they afraid of the virus or a bank run? The bank is in a small town outside of San Angelo. I don’t want to put any money in my account right now if there is to be a banking holiday.

    UV lights have been used to purify water. Ozone generators have been used to purify air. Right now that is the best I can do other than boil water to sterilize what I can.

  • For the last year or so, I’ve been unable to find any pool shock consisting of Na hypochlorite. It’s all some other chemical instead. Even the laundry bleach tablets labelled as “bleach” are not Na hypochlorite.
    It’s almost as if stuff has been substituted, knowing how we will react.
    I won’t even address the “food sawdust laws” being discussed.

    • I, too, am unable to find “pure” forms of pool shock. I have been looking off and on for a couple of years since I first read this! Anyone have suggestions for where to find it?

      Many thanks!

    • Roberta, try Ultima T.K.O. Pool Shock, which is available on Amazon. It has, as I recall, 73% Calcium hypochlorite as its active ingredient.

    • I went to Lowes today and looked online. I’m having problems finding this without added chemicals too.

    • You can’t buy powdered sodium hypochlorite onky in liquid…. CALCIUM HYPOCHLORITE is pool shock.

      You can buy at chemical supply places that supply mega places like dairy factories or massive food processing facilities.

      It’s cheap $50 will buy you 70 lb of it

    • Give them brewers yeast for the niacin if they do not have access to fresh greens. I use starter/grower. Starter has to much calcium and will cause angel wings. Then I switch to grower/finisher. Since I have a lot of chickens, the laying ducks use the layer too. The young ducks love bugs. My ducks love when I get bones from the butcher. They attack the bones for the fat and marrow right next to the dogs. If baby’s keep them warm. Normally they stand under their mother at night for warmth and protection until they feather out. Keep the babies out of water until they are bigger. A small water dish will turn into a bath if you are not careful. Make it shallow.

      • Thank you very much! They are about 2 or 3 weeks. Very noisy ! Is there a way we could communicate more directly? Would love to chat

  • I too have had major problems getting the unadulterated pool shock without the additives and the right percentage of the main ingredient. I finally did find some though. I would suggest that this article address the challenges of storing this chemical. It will corrode metal. Even when stored in plastic pails, the corrosive effect is still present to the point that it can corrode items in the same room where it is stored. When I contacted the manufacturer of the product I purchased, they strongly advised that I purchase it in smaller sized containers (their smallest was 5#) as opposed to the large 25# plus containers as once the container is opened, even when you close the cap tight, it is likely to corrode stuff. This is a link to one of the manufacturers of pool shock.
    Please be advised the trade name on the product may not be the actual manufacturer of the product. I would suggest before buying any pool shock to use for drinking water that you read the Materials Safety Data Sheet (MSDS) for your particular brand and I even phoned this company and they gave me an excellent education on their pool shock. Forgive my paranoia but I have read about 10 ways to use pool shock for drinking water and they each tend to take a slight deviation that could result in a not so good outcome. Do your own due diligence.

  • This is good for sterilization and cleaning. But you should never use bleach, or any type of pool shock for water purification unless absolutely dire necessity. Calcium hypochlorite is extremely toxic and unless you have a very good filtration system can not be removed from the water. For natural non toxic purification use colloidal silver 1 ounce per gallon, its naturally anti viral and anti bacterial and is harmless to drink. In any critical situation you need to be very careful of the harsh chemicals that you put in your body.

    • Just no. Please read up on some basic chemistry before poo-pooing pool shock. You obviously don’t know what your talking about.

    • The lord pharmacist for applies to everything: dosage make the poison. In other words, anything filled properly is safe. Anything in excess is harmful. Table salt in a dose of a few shakes is fine. However spoonful per meal is harmful.

      The pool shock is fine when diluted as demonstrated by everyone safely using their pool, including kids.

      The chlorine is largely evaporated off in a few hours, especially if the water is poured back and forth between buckets to aerate it.

      The pool shock type to avoid has descriptions of controlling algae, scale, and hardness. The cheaper version is the correct one. I found some at the big orange box.

      But you really should do a bit of proper research before spreading your harmful propaganda.

  • A slightly easier recipe for the pool shock chlorination method is to use 1/4 teaspoon of shock to 1/2 gal of water. From that concentrate, add 6oz (1/2 coke can) to a 5gal bucket of water. This recipe resizing for more to what people will be interested in making. Also less water and shock is wasted.

    We noted by several people, shock is corrosive. Also it outgasses so a closed container store not isolate it from adjacent tools. Temperatures over 95F cause a rapid degradation of the shock. So for me, storing it outside, limits its life to a single summer. Storing it anywhere else damages the stuff near it.

    It is a strong oxidizer. Do not mix or store with liquid organics such as gas and oil.

  • This article is very helpful, but I think there’s a rather important fact missing in your recipe. Once two gallons of bleach is made, there’s no information on what concentration is in the final product. Does the recipe make 6% or 8.25% concentration of bleach. Getting it wrong or guessing may not be the best solution (pun intended).

    Thanks in advance,
    F. McNeely

  • Is there a particular brand(s)? I can’t tell from any of the ones on Amazon if they contain other chemicals that would make them unusable per this article

  • BE CAREFUL! Much of the pool shock now available is dichlor (sodium dichloro s triazinetrione). Do not mistake it for calcium hypochlorite, it is MUCH stronger.

  • Thanks for the informative article. I know this article is a few years old. But I went to wally world today and a bottle of bleach ( 121 oz) ran me 6 bucks. Supply chain issues and inflation is making things outrageously expensive. I said never again, and will DIY bleach from now on. Again tks.

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