Jodie Weston
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If I were to ask how many of you store liquid bleach along with your other prepping supplies, I am certain that a good percentage of you would raise your hands. Liquid bleach is a powerful disinfectant and sanitizer but did you know that there is something better? Something with an almost indefinite shelf life that is inexpensive and takes almost no room to store?
That something is the chemical Calcium Hypochlorite most commonly known as Pool Shock.
I have known about Pool Shock for years but because it is not readily available in my area, I never took the time to search it out so I could stockpile some for my own emergency preps. That has now changed and today I plan to show you how to use Pool Shock the easy way, step by step.
Why Not Bleach?
Before we start, you may be asking “why not use liquid chlorine bleach?”. There are a few problems with liquid household bleach. It takes a lot of room to store bleach plus the usable shelf life is only six months to a year depending on storage conditions.
The folks at Clorox say this:
The active ingredient in liquid bleach, sodium hypochlorite, is very sensitive to high heat and freezing, but under normal home storage conditions, it should still perform well for nine to twelve months.
In addition to limited shelf life, there is another problem. I have had reports from Backdoor Survival readers telling me that in their area, they can only purchase “Clorox Ultra” which is concentrated. When I called Clorox to ask how to use concentrated bleach to purify water, they said that it was not intended to be used in that manner and why would I want to do that anyway. Seriously, their representative actually said that.
Pool Shock – The Boilerplate
When I started doing research for this article, I visited some of the most respected survival and preparedness blogs and forums for background material. After all, pool shock is pool shock and there must be some standards for use, right?
With just one exception, all of the sites I visited included this boilerplate from the EPA:
You can use granular calcium hypochlorite to disinfect water.
Add and dissolve one heaping teaspoon of high-test granular calcium hypochlorite (approximately ¼ ounce) for each two gallons of water, or 5 milliliters (approximately 7 grams) per 7.5 liters of water.
The mixture will produce a stock chlorine solution of approximately 500 milligrams per liter, since the calcium hypochlorite has available chlorine equal to 70 percent of its weight.
To disinfect water, add the chlorine solution in the ratio of one part of chlorine solution to each 100 parts of water to be treated. This is roughly equal to adding 1 pint (16 ounces) of stock chlorine to each 12.5 gallons of water or (approximately ½ liter to 50 liters of water) to be disinfected.
To remove any objectionable chlorine odor, aerate the disinfected water by pouring it back and forth from one clean container to another.
Have your eyes glazed over yet? Mine have. Being an accountant, I like to deal in absolutes so what is this business about “one heaping teaspoon”? Plus, what’s up with the references to “approximately” and “roughly”?
I decided that it was time to do my own testing, and sure enough, each time I measured out a heaping teaspoon, I had different results; they ran the gamut from 1 1/4 teaspoons to 2 teaspoons. This made my head hurt.
Another thing. Over and over I read that you should use pool shock that is a minimum of 78% calcium hypochlorite with the balance being inert ingredients. Fair enough, but there are two problems with this. First, what you find locally maybe 68%, it may be 78%, or it may be something else. Second, the EPA makes no such recommendation or at least none that I could find. They simply say “high-test”.
Did I mention this made my head hurt?
But there is more. I actually found a couple of sites that said to use one heaping tablespoon of Pool Shock for every two gallons of water! You know, just because you find something on the internet does not mean it is true.
My conclusion? The exact amount and the exact percentage does not matter as long as it is within a reasonable range and close to the EPA standard. I do think it is important that the pool shock does not contain other additives that may or may not be safe even when highly diluted. Other than that, however, it is my belief that the precise percentage of Calcium Hypochlorite to inert ingredients does not matter as long as it is 68% or higher.
For my own use, I settled on 1 teaspoon of pool shock per gallon of water when making up my stock chlorine solution. Then, to disinfect water, I used 3/4 ounce of my pool shock solution to treat a gallon of water. This makes it easy to calculate how much to use for water disinfection, regardless of the size of your container.
Step-by-Step: How to Purify Water Using Pool Shock
The first thing I did was to gather my supplies. Notice that I used eye protection goggles and rubber gloves. Other supplies included an empty bleach bottle, funnel, shot glass, and measuring spoons.
I verified the size of my stock chlorine solution container, namely a repurposed bleach bottle. My bottle held 1.42 gallons and I wrote this on the outside with a Sharpie pen. My intent, however, was to only prepare 1 gallon of stock solution to keep the math simple.
After donning my protection gear, I added water to my stock solution bottle, carefully measuring the quantity. I used exactly one gallon of water.
I then measured out some pool shock; one level teaspoon to be exact. I put the cap back on the bottle and swished it around a bit. I gave it a sniff test and it definitely smelled bleach-like.
The next step was to purify water. I wanted to make drinking water and for me, the smaller the jug the better. I chose a 64 ounce repurposed apple juice jug. Remember the easy math? The EPA says 1 part chlorine solution to 100 parts water so the math is 64/100 = .64 ounces.
Keeping things easy, that translates into approximately 2/3rd ounce. Remember, the EPA guideline uses the word “approximately” all over the place. That was good enough for me. To easily measure the proper dilution, I used a mini shot glass that had measurement markings along the side.
Be sure to pour your pool shock into your water and not the other way around. The last thing you want is to splash the solution on yourself on the surrounding surfaces (although you have probably noticed that I did this outdoors).
After preparing my newly purified drinking water, I drank up. Three things. I did not throw up, I did not get diarrhea and I did not get sick or die.
I am comfortable with the results even though the solution I made may have been slightly stronger than the EPA guidelines. Then again, given the vagueness of the EPA guidelines, perhaps my measurements were spot on.
Note: I did not find that my water had an objectionable smell or taste. True, it was not sweet tasting like the water coming out of my Royal Berkey but it was palatable. If your own purified water has an unpleasant odor, simply aerate it by pouring it back and forth between clean containers. This trick applies to any water, not just water treated with pool shock.
Label your pool shock solution. This is powerful stuff. Get out your Sharpie and label the jug with as much information as you can. Store it, in the same manner, you store liquid bleach, up high and away from pets and children and in a location that is cool, dark and dry.
Also, store your unused pool shock safely. Because it is corrosive, I chose a mason jar with a plastic lid. Plus, rather than empty the pool shock into the jar, I sealed the plastic bag it came in with a clip and stuffed the bag inside of the jar.
Other Handling and Storage Considerations
I contacted the manufacturer of the pool shock I purchased and requested a Material Safety Data Sheet on the product. They promptly responded and here is what it said about handling and storage:
Keep product tightly sealed in original containers. Store product in a cool, dry, well-ventilated area. Store away from combustible or flammable products. Keep product packaging clean and free of all contamination, including, e.g. other pool treatment products, acids, organic materials, nitrogen-containing compounds, dry powder fire extinguishers (containing mono-ammonium phosphate), oxidizers, all corrosive liquids, flammable or combustible materials, etc.
Do not store product where the average daily temperature exceeds 95° F. Storage above this temperature may result in rapid decomposition, evolution of chlorine gas and heat sufficient to ignite combustible products.
Recommendations
Now that I have been through the process and understand the math, I am comfortable using pool shock to purify water for drinking, hygiene, and sanitation purposes. It is not, however, an excuse for not storing water nor an excuse for not having a supply of traditional water purification liquids or tabs that are pre-measured and simple to carry with you in bug-out-bags and emergency kits.
As far as I am concerned, the pool shock I have purchased is reserved for dire emergency use, period. Yes, I feel it is safe, but it is still a powerful chemical solution as is liquid bleach. I will use it as the water purification method of last resort and if the time comes, I will be thankful I have it on hand.
Disclaimer
I have to say this: I am not a chemist and I am not an expert. My methods are my own and they work for me. That being said, if you have any hesitation at all, visit other resources including the EPA and make the decision to use pool shock your own and not just something someone told you to do. Here is a link: Emergency Disinfection of Drinking Water.
The Final Word
Everywhere you look you will see a recommendation to store bleach for water purification. I have made that recommendation and so have many, if not most, of my blogging peers. What you may not have seen is that liquid bleach has a limited shelf life of 6 to 12 months. I fear that this could be leaving a lot of people ill-prepared to produce safe, potable water in an emergency.
This means that a person that began prepping a year ago, and does not know to rotate their bleach, is already living with false security when it comes to water purification. And what about people that have been prepping longer?
As long as pool shock is stored properly, it will have an almost indefinite shelf life plus, a small one-pound package will treat many thousands of gallons of water. Ten thousand to be exact. It can be mixed and used as potable water and as a disinfectant, just like bottled liquid bleach. So if you have a water storage tank and need something for emergency water disinfection, a hypochlorite solution could work out well for you.
At the end of the day, do your own research and decide for yourself.
Enjoy your next adventure through common sense and thoughtful preparation!
Gaye
88 Responses to “How to Use Pool Shock to Purify Water”
This site has instructions for using pool test strips to evaluate the strength of your solution. Should make the process a lot more precise and predictable.
//livingprepared.blogspot.com/2013/05/make-you-own-full-strength-bleach-from.html
Thank you so much for doing this research!
You stated you were not a chemist. I am, and I’m a nutritionist.
Pool shock is ok for 1 glass. The ‘other ingredients’ will kill a compromised person in 1 day or a normal person in 3 days. Pool shock requires stabilizers and bacterostatics and because this is not a food item, they are not required to tell you they are in there. It states right on the package to not drink the pool water or use for water purification. The active chemicals are not stable, not pure, and certainly not for ingestion.
If you actually use your head, there is a great reason why liquid bleach and Ca(OCl)2 are not used by public water sources: they are toxic. It is the reason why the more expensive Cl2 gas is used or NaOCl is used.
Hi Chris, I am confused.
You said “there is a great reason why liquid bleach and Ca(OCl)2 are not used by public water sources: they are toxic.”
My understanding is that chlorine bleach works precisely because it is toxic, as are the others. If they weren’t toxic, they wouldn’t kill bacteria or viruses. My understanding is that C12 gas is used because, for the quantities a municipal water system handles, while dangerous to handle, it works very well and is cheaper. Bleach isn’t cost effective in those quantities.
I did some research a while back on using bleach, (Clorox specifically) for sterilizing water in an emergency. The American Red Cross “Food and Water in an Emergency” page recommends it. Their page:
//www.redcross.org/images/MEDIA_CustomProductCatalog/m4440181_Food_and_Water-English.revised_7-09.pdf
Scroll down to their pages 11-12 for using bleach.
The ready.gov site recommends bleach for storing water: //www.ready.gov/managing-water Clik on the Water Treatment tab for using bleach to treat suspect water*.
While I am not personally familiar with the reliability of the Family Survival Planning page, it has warnings about using iodine, along with bleach instructions: //www.family-survival-planning.com/how-to-purify-water.html
The Clorox company’s disaster page for purifying water:
//www.clorox.com/dr-laundry/disaster-preparedness-purifying-water/
All of the professional opinions I can find say that fresh bleach works just fine, and that since bleach breaks down, fresh bleach is stronger than older bleach. Year old bleach isn’t worthless for purifying water, but you have to use more.
None of this addresses the issue of using pool shock to treat water. I would like to see a statement from a manufacturer about safety. They may be highly reluctant to state that it is safe, even if it is, if it is not a registered disinfectant for drinking water. Your comment about their not being required to state other ingredients because it is not a food item should raise a big warning flag for all of us: I would want to know what is in it. Until I know I will continue to rely on bleach, buying some fresh whenever we have a hurricane warning.
My understanding, which may be both flawed and dangerous, is that while a filter like an AquaStraw or AquaStraw Family size will filter out bacteria, cysts, and viruses, it will not filter out dissolved chemicals. For that one needs a purifier like an AquaPail. We have all three in our hurricane supplies.
It seems to me that the best water is the water which one has stored before an emergency occurs. After that, I prefer sterilizing with bleach. Down the list comes swimming pool water which I would run thru a filter and, ideally, a purifier.
* Of course, the ready.gov “Managing Water” page also says “Do not drink carbonated beverages instead of drinking water.
Carbonated beverages do not meet drinking-water requirements. Caffeinated drinks and alcohol dehydrate the body, which increases the need for drinking water.”
To my mind, that is dangerous misinformation: While caffein does increase urination, drinking a caffeinated beverage will, net, act to rehydrate you. It just won’t rehydrate you quite as much as plain water would. If one has the choice of drinking caffeinated drinks or not drinking, one is FAR better off drinking.
I bummed around North Africa, the Middle East, and Central Asia during the 1970s, and I guarantee that the Arabs, Persians, Afghans, and Pakistanis do not drink plain water: They drink tea and coffee. In areas like Jordan in the summer, where IIRC the UN recommends drinking 17 liters of water per day, the Arabs drink hot caffeinated beverages. Part of that is because brewing coffee and tea require boiling the water, which sterilizes it. Hot drinks also make one sweat, which in turn cools one off.
As for drinking suspect water without treating it: If your choice is drinking it or dieing, drink it. I took a train from Kerman, Iran, to Quetta, Pakistan during the summer. The train people apparently didn’t warn passengers that they must carry sufficient water themselves. While many did, a great many, including I, did not. We didn’t know.
It was three summer days and nights through the worst desert I have ever seen, sand as far as one could see, the train stopping while crew shoveled sand off the tracks, and there were knife fights over water. Ditch water, dumped in the ditch by the train to supply a small group of houses. People didn’t know how long the train would stop, they didn’t know how much time they had to fill bottles from the ditch, so they pulled knives and used them so they could get to the ditch water.
Pakistanis drank it, I drank it, and I later came down with infectious hepatitis, which is no small thing. Unless I had drunk that water, though, I would not have lived long enough to get hepatitis.
Oooops: I meant “LifeStraw”, not “AquaStraw” above. My apologies.
Penrod – when it comes down to doing it or not staying alive most people will do the things that they said “NEVER” to.
However, I personally think I would not have survived as a member of the Donner party!
As an ex water plant operator for 37 years and a everyday user of CS that I make myself, I’d like to make a comment. While I use CS for many things and own and read several books on the subject, I’m not sure if I would count on it for water purification. The main point that I have is this. If you use a generator to make your CS with, as most people do, your average dose in PPM comes in from 10 to 17 PPM. Most people use the 10 PPM as their everyday strength. I usually make a 10 and a 17 batch. I use the 17 for external things and the 10 for internal. A generator will make a higher dose but at a higher dose you will get silver starting to coagulate in the water which must be removed and you will use way more power and time to do this. You will also have to keep pulling the rods out and clean them so much that it’s just not worth the effort. When you may see CS for sell that says it is hundreds of PPM it has be made with a silver salt and is not true CS. My point on water is this…if you have a batch of 17 PPM and you want to treat a gallon of water, how much would you need to add? How long would it need to rest before it was ready? I have never seen a formula for this in any of my books. While I do not believe that it would hurt anything to add it to your water. I don’t think that I would feel safe using only that method. If anyone knows the formula, I would welcome this info.
Great information even if I can’t use it. Too many around me with allergies to chlorine. I too, use silver but never tried the colloidal silver so will investigate.
I’m told I’m teasing the local lab since I bring in water samples frequently. Why? I’m testing how to purify with just what might be at hand if/when someone desires what I have more than do. 😉 I’m preparing for that too….better to walk away living than the alternative. 😉
Hi, Gaye,
I’ve really been enjoying your posts…I’ve gotten more useful practical real life-type information from them than from any of the many prepper sites I’ve been lurking about on. It’s appreciated!
As a prior-military father and husband, I’ve been prepping since the early ’90’s in order to be prepared for whatever nature (and our government) has in store for us…in that vein I’ve found a great appreciation for the common-sense practicality ideas like pool shock water purification.
I’d like to formally request you do some experiments with the colloidal silver and enlighten us all on its properties as soon as possible.
Thanks again for all of your work and the sacrifice that goes along with any blog.
Please be sure to always add CHC into water…..never put the CHC in the container first adding water to it in a small container can have a volatile reaction.
And for the record, the more bacteria in the water, the faster the chlorine is used up. Sunlight also uses up the chlorine faster…that is why the recommend shocking at night.
Hi Joanne, I agree. As Gaye said: “Be sure to pour your pool shock into your water and not the other way around.”
The reason: Putting pool shock (or any other chemical) into water creates a diluted solution which slowly becomes more powerful as you add more. Depending on the chemical, the reaction may create heat, and you do not want to inadvertently create a great deal of heat.
Adding water to the chemical creates an extremely concentrated solution, may create a great deal of heat, and can result in an explosion which throws hot, toxic, highly alkaline or acid chemicals all over, including on you.
So, the simple way to be safe: add chemical to water, not the other way around.
Exactly, treat the 2 liter of water like a pool.
One always throws the powder into the pool water; likewise, the CH is put into the 2 liter.
I would also suggest that this should be added to everyone’s barter supply list or your gift packages you plan to give away.
“Make sure that Calcium Hypochlorite is the only active ingredient in the product and at 65% or greater, (Note: You will not be able to find this concentration at Wally-World, you will need to go to a pool supply store) with no added anti-fungal’s, or clarifiers, if not you can seriously endanger you and your family.” Quote from article below.
Here is an article that also looks at the 1:100 ratio and how to purify small amounts of water. //www.thesurvivalistblog.net/how-to-carry-200-gallons-of-water-or-more/
Is there a particular reason that you mix up the solution first, and then purify water using the solution? Why not use the pool shock (in the proper quantity) to purify the water directly?
To give you an idea of its strength, 1 pound treats 10,000 gallons of water. Breaking down the measurements would be unwieldy. Plus, as I mentioned above, Pool Shock is a powerful and potentially toxic chemical if not used properly. It is much safe when used in its diluted form.