Guest Post by D. Holden
Introduction
Water: the source of life. One can live weeks without food, but only days without water. Water makes up approximately 60-70% of a human’s body weight. It is, and should be, one of the most important considerations in planning for a long-term disaster scenario. Given that the average human will need one gallon per person per day minimum, storage of large quantities of water quickly becomes impractical and therefore won’t be discussed in this post. This article also assumes that you don’t have a private well that is completely off the grid. If you have the land, if the city or county allows it, and if you can afford it, then by all means, make getting a private well your first order of business!
So how can one find safe water after a major disaster? If you don’t have a well with a solar or hand pump, you’ll most likely have to rely on natural sources of water such as streams, ponds, lakes, or rivers. It would still be quite dangerous to drink directly from stream or river, even if it appears completely clean and clear. There is always the risk from Giardia and Cryptosporidium, not to mention the chance of a dead animal just upstream unbeknownst to you. Even a bit of animal or human excrement upstream can make a person seriously or deathly ill. If you use natural sources of water, then some form of filtration or purification will be necessary.
So, what to do? Well, you have a few options:
1. Filters
First, you could invest in a ceramic filter, like the British Berkefeld Ceramic Water Filter. While a bit pricey, they’re both highly recommended and receive terrific reviews. I’ve used this particular brand in West Africa for many years, and I admit they are convenient, safe, effective, easy to maintain, and long-lasting. The ceramic filters only need an occasional cleaning and can withstand cleaning many times before needing to be replaced.
They are definitely worth the money, but you should note that they only filter out organic contaminants and sediment from water. Since they don’t have anything like activated charcoal, they don’t filter out chemical contaminants. I don’t imagine most sources of water would contain dangerous levels of chemicals, but if you take water from a river or stream that is next to a typical commercial farm, there is the risk of ingesting pesticides and herbicides from the farm runoff. It’s the same for water that near an industrial plant. This should not be a problem for most people, but it is good to be aware of the possibilities. Know what is upstream!
For a good portable filter, you could go with the Swiss-made Katadyn Hiker or the Hiker Pro. A wonderful benefit to these filters is that they are extremely portable, which makes them vital components of bug-out bags. Another benefit is that they remove virtually all organic and chemical contaminants.
The down side is that you only get about 200 gallons out of each filter, and the replacements add up very quickly. However, if you want more filtration for your money, like say 13,000 gallons worth, you can go with the Katadyn Pocket Water Microfilter. While remaining very portable, it uses a simple ceramic candle similar to the British Berkefeld. Just note that as with all ceramic candles, it won’t filter out chemical contaminants.
An interesting, albeit more primitive option, is to build a BioSand Filter. They’re not perfect, but they are so rugged and easy to build and maintain that they are worth some consideration. They remove around 95% – 99% of all organic contaminants by way of an active “biological layer” and simple sand filtration.
These filters have largely been implemented in the humanitarian realm by organizations such as Samaritan’s Purse and Convoy of Hope. You can build them out of plastic or concrete, and they’re very low maintenance. Again, they don’t remove 100% of organic contaminates, so there’s still a very small chance of getting a water-borne bug of some kind, but it’s a good semi-permanent solution when your other options run out.
Since the biological layer takes some time to develop, you could use other short-term methods listed here to carry you over until this filter is fully functioning. They really do save lives in the third-world, so it’s worth some investigation, at least for a backup option. You can find plans online for building them.
2. Boiling
There’s always the idea of boiling your water, but for that you would need a large source of energy, perhaps something like wood or propane, not to mention a large amount of time as well as storage. Boiling water may work in a pinch, but it would be extremely cost and resource prohibitive in the long run, especially in a long-term grid down scenario.
On a personal note, many years ago, I went on a weekend camping trip and severely underestimated my water demands, all while carrying foods high in sodium. Needless to say, I became very dehydrated and had to stay up all night boiling, cooling, and drinking river-water. It worked great, but due to the time and the energy necessary to boil water, I quickly realized that relying on this method of water purification in the long-term is not a good idea.
3. Chemical Disinfection (i.e. Chlorination)
In a common local disaster scenario (hurricane, ice storm, tornado, etc), organizations such as FEMA and the Red Cross suggest using unscented household bleach (5.25 to 6.0 percent sodium hypochlorite) to treat water. FEMAs instructions are as follows:
“Add 16 drops (1/8 teaspoon) of bleach per gallon of water, stir, and let stand for 30 minutes. The water should have a slight bleach odor. If it doesn’t, then repeat the dosage and let stand another 15 minutes. If it still does not smell of chlorine, discard it and find another source of water.”
This method is not really generally recommended for long-term use. Plus, bleach has a limited shelf-life (around 6 to 9 months), so you’d have to rotate your supply often in a long-term disaster. To get around this limit, some people instead buy calcium hypochlorite (rather than the sodium hypochlorite in bleach) in the form of “pool shock.” It comes in granular form, is relatively stable, and has a surprisingly long shelf-life.
I’d be careful with this stuff however, as storage can be dicey (I’ve heard stories of it corroding surrounding items when not stored properly), and one needs to be aware of proper measurements and mixing amounts. I’m sure with enough research and preparation, the granular calcium hypochlorite could be a fairly good backup method of water purification.
4. Solar Disinfection: SODIS
SODIS, or SOlar DISinfection, is the cheapest and easiest of the methods listed here. Solar disinfection only requires two things: clear plastic (PET) bottles and sunlight. Find soda or water bottles with the PET recycling mark that are clear and colorless, 2 liters or less in volume, and preferably no more than 4 inches in diameter. Fill them with water, close the cap, and lay them on their sides in full and direct sunlight for a day.
It’s better if you place them on a shiny surface, such as corrugated metal roofing, and angle them towards the sun so that they sun’s rays will strike the bottles more directly. If the water is cloudy or turbid, filter the water with cloth or cotton until it is clear. Keep the bottles in direct sunlight for at least 6 hours. If the sky is cloudy, you will need to keep the bottles out for two days.
So, how does it work? The strong ultraviolet light (UV-A) from the sun not only destroys bacteria directly, but it also reacts with oxygen to create oxygen free-radicals which can also kill bacteria. One way to improve the effectiveness of the process is to aerate the water by shaking it. To do this, fill the bottle 3/4 full, cap it off and shake it. Then fill the bottle up the rest of the way until it’s completely full. This oxygenates the water and increases the amount of oxygen free-radicals created by the sunlight.
Conclusion
This is surely not an exhaustive list of water treatment methods, but I wanted to list some common ones for consideration. Rather than rely solely on one method of water purification, I would consider having many methods in one’s survival arsenal. So goes the preparedness maxim, “two is one and one is none.” This definitely applies to methods and ideas as well.
Do you have any other methods not considered here? What do you think?
{ 20 comments }
In regards to bleach availability:
Hypochlorite salts are easily made by reacting chlorine gas with water or an alkaline solution. It sounds daunting, but it’s not all that difficult.
The easiest way to generate chlorine gas is to electrolyze ordinary table salt. Alternatively, you can react hydrochloric acid with sodium chlorate. Both are generally freely for sale as weedkiller and cleaning agent respectively.
You’d need a small ventilator or airpump (the kind you pump with your foot to inflate pool animals works great, as they are cheap and) have no parts that readily corrode, but the rubber seals will suffer over time) to funnel chlorine gas into a tube, then have your alkaline solution or plain water spray down over the gas flow. (or it can drip through a few dozen pinholes poked trough a balloon. The gas flow must be allowed to exit out the top, the bleach solution runs off at the bottom … and behold, you very own “counter current spray tower”
The alkaline solution can be a solution of baking soda, white chalk, sodium hydroxide (lye, drain cleaner, the other product of electrolyzing salt) or any other basic chemical)
On a more general note:
Practical chemistry is a skill that is (IMHO) overlooked extremely when it comes to prepping. It is fun and educational even when everything is going swimmingly, and when things go bad … anaesthetics, antibiotics, soap, bleach, explosives (for tree stump removal), dyes, GLUE
And you KNOW distilling is going to be a handy skill :p.
Hi, the solar technique looks like the best to me! I hate the idea of running out of filters or additives. But question – what is the best water storage method? I would want to have a bunch of clean water in reserve for the cloudy days. Is it possible for water to become re-contaminated while in the storage unit?
How much storage are we talking about? I have some 6 and 7 gallon water containers for storage, and they’re about the largest size that’s manageable by both me and my wife. As long as you keep the water in a sealed container, you shouldn’t have to worry too much about re-contamination. However, this is where some bleach or calcium hypochlorite would come in handy. Theoretically, when I put aside 7 gallons of city water for my own storage, it’s supposed to be clean enough that I don’t need to disinfect it. But I go ahead and add 8-16 drops per gallon anyway, just to be safe. But really, if you have enough bottles for SODIS, especially the 1.5 liter size, then the bottles themselves would be adequate storage (if you calculated your needs correctly) because you would be rotating them out.
I was wondering about potassium permanganate water purification. Does it work to add a few crystals to water?
I really like the biosand filter. No consumables, field expedient construction and filtration that tests better than a ceramic filter.
Looks like another project to add to the list. Thanks for the inspiration.
Google WAPI (Water Pasteurization Indicator)
Water needs to be heated to only 149 deg to be pasteurized. You still need a heat source but solar heating becomes easier. A lot of fuel is wasted actually boiling.
Very good point Robert. It’s amazing how the myth persists that you need a good rolling boil for 10 minutes in order to make water safe to drink. Nothing could be farther from the truth. In the wild, I get the water just up to the boiling point for pasteurization. It saves time, saves my limited fuel, and is very safe. I know I’m still going a touch higher than what’s necessary, but this is an area where I’ll err on the side of caution.
Great information here. While reading this, it occurs to me that, just like no single firearm is well suited for all jobs, no single water purification method is well suited for all situations as well. Some methods are great on the run, while others won’t work at all. Some rely on expensive equipment and replacements, while others can be done using only commonly found materials. Some are ideal for reasonably safe water sources, but won’t work in highly contaminated scenarios. As good little preppers, it behooves us to know and have equipment for a few different methods, so that we can tailor our approach to the situation.
I was surprised that iodine was not on the list. This is one of the staple methods of water purification that I have used in the past and that I will rely on in a bug-out scenario. Like chlorine, it is not recommended as a long-term solution, but it works well for short-term, on-the-go scenarios. Iodine will kill just about everything in the water, even the stuff that will get through most water filters. It will not, of course, get rid of chemical and mineral contaminants, and you have to live with the taste.
The most common form of iodine water treatment is the iodine tablets that are sold in most sporting goods stores and departments. These tablets are cheap, easy to use, and come in an itty bitty bottle that is easy to pack. However, once you open the bottle you have to use the tablets within a few months. A single bottle will treat about 6-12 gallons of water.
My perferred method is Polar Pure iodine crystals. The bottle is a bit bigger than the iodine tablet bottles, but not by much and a single bottle will treat 500 gallons of water. This form of iodine also has an indefinite shelf life. They are available on Amazon for under ten bucks a bottle. Given their small size, low cost, shelf life and treatment capacity, I have one bottle in each bug-out bag and one in each car.
I’ve wanted to get some Calcium Hypochlorite to use as a water purifier, but every sample I’ve looked at reads something like:
Calcium Hypochlorite .. 2%
Inert Ingredients………98%
Is that okay? what are these inert ingredients, and are they safe? Is this what others are using?
Thanks for any feedback.
AZGuy
I’ve been told that this will work well. Storage life is pretty much indefinite.
http://www.inyopools.com/Products/22300006058112.htm
Thanks, Charlie. That sounds more like it. The stuff I keep looking at is usually at Wallymart or Home Depot. Probably made in China. I’ll order from the link and cross another item off my prep list. Thanks again.
AZGuy
A friend of mine ordered from them. He contacted them and was told that the 38% or so that is not Calcium hypochlorite is just inert ingredients.
He had looked at the stuff at Walmart and rejected it for fear of other ingredients. Another thing, since this stuff is much more concentrated, the other ingredients will be a much smaller % of the total solution in the treated water.
I haven’t ordered mine yet but intend to soon.
Don’t bet there aren’t any chemical contaminants in water!! Bet there are! Especially after any wide-spread disaster the watch dogs that protect us from spills and intentional dumps will be taking the day off. Everything from gasoline, dry cleaning chemicals, industrial waste, etc could be in that water, especially if you are near a city or large town. In some areas, even deep wells have traces of really scary stuff.
Being a self builder and publisher (past) of sustainable homes calendars, I ran across many books, articles and people who use a variety of systems to purify and re-use their water. Including composting human waste (Humanure Handbook) and redirecting/reusing dish water to irrigate gardens.
Look into a small but large-format pamphlet called “Safe Rainwater Collection” by Charmaine R. Taylor. Originally written for rooftop water collection and purification, but methods can be used for other water purification needs when all else fails and you don’t have money for a filter. DirtCheapBuilder.com
One method uses slow sand filters varying degrees of pebbles, sand, carbon and cotton as a filter system. Provides various methods of filtration in this natural manner and how to construct them.
Deb, sand filters are in use every day in municiple water treatment systems. They typically are fed from the bottom up so that the “raw” water more or less perculates up through the layers of sand, charcoal and gravel and is drawn off the top.
The original British Berkefeld ceramic filter – Doulton Sterasyl Candle – doesn’t have charcoal, but the newer Doulton Super Sterasyl Candle does. According to one website (http://www.pwgazette.com/gravity.htm),
“As a carbon filter it is marginally effective and should not be considered comparable to a carbon block cartridge. It’s about a 50% remover of chlorine on a pressured system, but as a siphon filter where flow is greatly reduced it does a much better job. Lifespan is shorter than the Sterasyl because the carbon core will eventually be exhausted.”
Carbon blocks are considered superior to granulated charcoal (e.g. Brita, Pur, etc.). I just laid aside a quantity of Brita filters, so that my treatment process for rainwater catchment is:
1. Bulk filter (get out the big stuff to avoid clogging other filters
2. British Berkfeld
3. Chlorine (Bleach if available and active, stored Calcium Hypochlorite otherwise).
4. Charcoal filter pouring water through Brita refrigerator bottle.
Agree that solar pasteurization is a great way to go for long term applications.
I built a number of SODIS units, AFTER I read the article where they are used in Africa. It seems that not only should the bottles be of the clear plastic PET type, but they should only be filled 2/3 full. Also it works much better if the bottles are painted a flat black on 1/2 of the bottle ( their backsides) for the UV rays to react even better.
I did some tests here in Arizona, and man do they get HOT!
I then let them cool after 4+ hours in the full sun, and the water was quite pleasant to taste!
Following that, I built a box of hardboard, lined it with aluminum foil and discovered it worked even better!
Not to be finished by any means, I built another box, and lined it with mirrror tile! Now we are talking some heat, UV, and high reflection of the sunlight into those bottles!
My box holds 6, 2 liter bottles at one time.
I have had the misfortune to read on some internet sites that they intend to distill their water to drink….
Can it be done?
Yes.
Is it healthy?
NO.
The human body NEEDS the minerals ( nature’s recipe) which are in the water we normally consume.
Distilled water has many uses, BUT, human consumption is NOT one of them.
Boiling water:
I get a KICK out of reading the different boiling times, as recommended by so many…
It is just NOT necessary.
Once water reaches the boiling point ( regardless of the altitude!) it is safe to drink, ( after cooling of course!).
There is NO need to boil water for 1 minute, 10 minutes, 30 minutes. The temperature of 212 degrees F. is all that is required, and even that is OVERKILL! At 165 degrees pasteurization takes place ( see milk!), at 190 degrees, all pathogens and microorganisms are killed effectively.
212 degress ( boiling point of water), is used just as a measure since most people don’t carry a thermometer in their pockets!
IF you were to boil Phoenix water for any time at all, you’d NEVER touch the stuff again! It just concentrates the garbage in it and makes it taste horrible! It leaves a white residue on any pot you use and regular cleaning is required for all coffeee makers, to get the GUNK chemicals out of them!
Katadyn Pocket Water Microfilters have been my choice for purifying water for a long time and I have two of them with many extra filters. Given that ceramic filters don’t filter out chemicals, I run the water filtered by the Katadyns through a Brita water filter which removes most of the chemicals. I use a Brita on a daily basis and I keep more than a year’s supply of Brita filters on hand at all times.
I grew up drinking cistern water that was filtered from rain water via downspout into a 24″ x 24″ x 30″ deep open top brick tank that was filled with rock, pebbles, large sand, small sand & charcoal and that tank released, at the bottom through a pipe, into an attached smaller brick and cement tank that had fine sand and charcoal in it with a concrete removeable lid. That water went into the cistern after filtering through. We drank and cooked with this water everyday for 30 years, hand pumping water into a bucket and bringing it into the house. Every few months we poured a cup of bleach in. The house had running water inside and it was brought in via water tanks from the nearby city and put into a different well. We did NOT drink that water, only using it for the bathroom. We are all still alive and healthy 30 years later.
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