Water Purification: Simple and Inexpensive Methods

Pure_Water-LittleGirl-GlassIn a disaster or emergency situation your source of drinking water may become contaminated, so it is important to know how to purify it before drinking, brushing your teeth, and before rehydrating or cooking food with water.

After an earthquake, major storm or flood, even if you still have running tap water it may have become contaminated.  Even bottled water which has been in flood water, or exposed to high temperature or frozen, may have become contaminated.

When in doubt, purify.  Even pristine-looking mountain water, river water, and crystal-clear lake water usually contains giardia, a protozoa which can make you violently ill.  This article will provide you with what you need to know to purify your water quickly, and inexpensively.

First, it is important to understand that most water filters do not purify water, they only clean it.  And clean water isn’t enough.  It must be purified because even clean-looking water may be contaminated with illness-causing bacteria, viruses, and other contaminants.

You need to both clean your water, and purify it.

An expensive purification system isn’t necessary.  You can make your water 99.9% safe by following this simple 2-step process:

Step-1:  Clean Your Water.   Step-2:  Purify Your Water.

If your water is already clean looking and clear, start with Step-2.

Contaminated-Faucet-WaterStep-1:  Clean Your Water

If your source of water is cloudy, off color, dirty, or might be contaminated with effluent (sewage, factory waste, animal excretions, etc.), or fertilizers or pesticides, you need to do what you can to clean it before you attempt to purify it.

Even if you have a household water filter such as a Brita, Pur, ZeroWater, or Clear2O (best of these four), these are not adequate for the task of purifying your water.  But they are helpful for cleaning water prior to purification.

Notwithstanding, since water filters are quickly clogged, water which is dirty or colored should be pre-filtered using one of the below methods.  It is desirable to use a household-type water filter for an additional level of cleaning, but the below water-cleaning process should be used first, so that your household-type water filter will have a longer useful life.

Wash-Bucket-FirstClean Your Water Containers:  If your canteen, water bottle, or container for storing drinking water might be contaminated, wash it – including the lid/top/cap, with soap and water before use.  Even if the water you are using for cleaning is contaminated, the soap will make the container safer than an unwashed container.

To clean the container, wash it thoroughly with soap and water, and then let it air dry, or dry it inside and out with a clean cloth.  If you are not able to dry it before use, wash it with fresh soapy water a second time.  If you will be using a funnel or some other object to transfer water from your boiling pot (or treatment container) to your drinking-water container, be sure to wash it, too.

filter-sock-200-micronMake a Water Filter:  There are all sorts of methods which can be used to filter water, but this is perhaps the simplest.

Put the foot of a fine-mesh nylon stocking or pantyhose inside a clean white athletic sock, and slowly pour the untreated water into the opening, positioning it so that the filtered water drains slowly into your clean water container.  If you don’t have a fine mesh nylon stocking and white athletic sock, use a combination of several layers of clean cloth or clothing items to accomplish the same filtering purpose.. You can use a paper coffee filter to filter the water again, to achieve better results.

Reposition your filter periodically so that the water is always flowing through clean fabric.  Keep the sock-filter from coming into contact with the cleaned water, and make sure that dirty water does not overflow your sock-filter and foul the water which has already been filtered.

If necessary, repeat this process until the water looks reasonably clear.  If you don’t have access to something which can be used to filter the water, draw water from the top of the water source, so that contaminants which have settled to the bottom can be avoided.

If your water source is a pool, pond or puddle, the surface water is usually cleaner, but the surface of stagnant-water source may contain oil or insect larvae, so use your best judgment.  A dish pan or bathtub can be used to temporarily store water, so that sediment can settle, before drawing out the surface water for filtering.

Purify_Your_Water-2Step-2:  Purify Your Water

The best purification method is to boil the water, or use a high-quality water purification filter system such as the Katadyn Pocket Water Filter ($370).  However, chlorinating the water with inexpensive household bleach or chlorine tablets is nearly as effective.  Other purification methods are generally less practical, but are included below in case they are needed.

Note: Neither the popular Chlorine or Iodine treatment methods will kill Cryptosporidium (aka/ Crypto), a common microscopic parasite that causes diarrhea. Boiling the water, or a filter designed for this level of purification, is required to neutralize difficult purification problems such as Crypto.

TOption “A”: Boiling to Purify Water

Cleaned water should be brought to a boil, and kept at a rolling boil for a minimum of 1-minute.  Boiling time should be increased for higher altitudes.  Since water boils at a lower temperature at higher elevations, it becomes less effective for purification, particularly if you are above 2,000 feet in elevation.  We recommend that you add another minute of rolling-boil for each 1,000 feet of elevation above sea level.  (At 5,000 feet of elevation, 5-minutes at a rolling boil).  And, that you consider using a second purification method as well, to provide more reliable results.  You don’t want to get sick.

Even a mild case of diarrhea can lead to serious dehydration problems.  Any illness during a disaster or emergency situation can render you incapable of performing essential activities, so it is important to exercise uncommon care to avoid illness and injury.

When you are boiling water, use a kettle or put a lid on your pot.  This will help keep the heat in, and make the water come to a boil faster, and you will use less fuel in the process.  If you don’t have a teapot or a lid for your pot, use another pot or tinfoil as a lid.

Exercise caution with this process.  Hot lids, your heat source, the pot used for boiling, steam or the boiling water itself, can obviously all cause serious injury if hot properly handled.  During an emergency situation it is important to exercise additional caution even with mundane tasks.  It may be difficult or impossible to obtain medical attention, so even a small injury can magnify your problems.

After boiling, let the purified water cool sufficiently before drinking.

Be sure to avoid contaminating the top of your water container when you transfer the purified water from the pot to your water container.

Note:  Since this method requires a stove and fuel, scarcity of fuel and the need for fire may make this method impractical or undesirable. But you have other options…

clorox-bottles-2-Yes_NoOption “B”:  Using Bleach or Chlorine to Purify Water

Stores such as REI (www.REI.com) sell small bottles of Chlorine Dioxide tablets, such as those made by “Potable Aqua” (20-tablest for $10, sufficient to treat 20-quarts of water).  Approximate Cost: $ .50 per quart of purified water.

These tablets are a compact and easy off-the-shelf method to purify water.  But after dropping a tablet into your water bottle, it takes 4-hours for the tablet to fully dissolve and treat one quart of water.  Be sure to shake or stir the water to speed the process of dissolving the tablet.

Liquid bleach is nearly as simple, and treatment is much faster.

Liquid bleach such as used for laundering clothes, is simple to use for water purification, and far less costly than chlorination tablets.  At less than 1-cent per quart of treated water, and ready in only 30-minutes, it is one of the most cost efficient and fastest water purification methods.

However, it is important to use “regular” bleach for water purification.  Scented bleach (lemon, lavender, etc.), “color-safe” bleach, and bleaches which contain additional cleaners or other additives, should not be used to purify drinking water.

A bottle of “Regular” bleach typically contains these ingredients:  water, sodium hypochlorite, sodium chloride, sodium carbonate, sodium chlorate, sodium hydroxide, and sodium polyacrylate.  If the front of the label indicates “regular” bleach, and does not tout other features such as scents, color boosting or added cleaning capabilities, it’s probably okay.

Bleaches which are labeled as “concentrated” are sufficiently similar to regular strength bleach (5.25 to 6.0 % sodium hypochlorite) that the below ratio of bleach-to-water remains the same.

Clear, clean-looking water 1-quart/liter(32-ounces) 2-drops
1-gallon(4-quarts, or 128-ounces) 6-drops
Slightly off-color or slightly cloudy water 1-quart/liter(32-ounces) 4-drops
1-gallon(4-quarts, or 128-ounces) 12-drops

How to Use:  After adding bleach to the water, stir the water (or cap and shake a not-quite-full bottle of water) to thoroughly mix the bleach with the water.  Then, let it sit for 30 minutes. After the waiting period, the odor of Chlorine should be detectable when you sniff the water.  If not, add a second dose (same quantity of bleach as previously used), and wait another 30-minutes.  If the water still does not smell like chlorine, discard the treated water and find a new water source.  If there is no other source, try improving your Step-1 water cleaning method, and try again.

Shelf Life:  An unopened bottle of Potable Aqua has a shelf life of 4-years if stored in a cool, dry place, and the bottle is unopened.  An unopened bottle of bleach under the same conditions has a shelf-life of 1-year.  A glass eyedropper bottle which has been completely filled with fresh bleach can have a shelf life of 1-year, whereas a plastic eyedropper bottle will generally only provide 6-month shelf life.

Safety Considerations for Bleach:  Carefully read the manufacturer’s safety and usage information which is on the bleach bottle label.  Bleach is not safe to drink except in the extremely diluted quantities as specified in this article.  Keep bleach and other chemicals away from children.

For Travel or For Use in a GO-Bag:  Fill a 2-4 ounce glass bottle, which has a glass eyedropper, with regular household bleach.  Be sure to label the bottle, and seal it tightly.  A dark colored bottle which keeps out light will help keep the bleach fresh, longer.  Old bleach can still be used to purify water, but the treatment dosage will increase with age.

Dry Chlorine:  More accurately called calcium hypochlorite, is commonly used for swimming pools, and has a longer shelf life than liquid bleach or liquid chlorine.  If kept dry, cool, and in a dark place, Dry Chlorine can retain most of its potency for nearly 10-years.  It is readily available from swimming pool supply stores, but since the strength varies by manufacturer, extra care must be used to determine the proper dose.  Also, since many pool products have additional additives, it is critically important that the right product is selected for the purification of drinking water.

For chlorinating water in rain tanks, first-time chlorination is often accomplished by adding as little as 7-grams of dry chlorine (1/4 ounce by weight) or 40ml (1.35 ounces) liquid pool Chlorine for 1000 liters (264 gallons) of untreated tap water.  Mix thoroughly if possible, or at least agitate the water to aid the mixing process.  Let the water stand for at least 24-hours before drinking.

To maintain safe levels of chlorination:  In a 1,000-liter (264 gallon) tank, each week add 1-gram dry (.035 ounce by weight) or 4ml (.135 ounces). Stir.  Let the water stand for two hours after treatment, before drinking.

Caution:  Proper dosage differs depending on the form and strength of the chlorine being used.  Calcium Hypochlorite is the solid form of pool Chlorine, and typically is 65% strength.  Sodium Hypochlorite is the liquid form of pool Chlorine, and often is sold in strength of 12.5%. Household bleach is Sodium Hypochlorite (NaHOCl) and typically ranges in strength from 5.25-6%.

Potable_Aqua-IodineIodine-Potable_Agua-n-PAPlusOption “C”:  Iodine to Purify Water

Tincture of Iodine (2% solution) and Iodine tablets are a water purification method that has been used for many years.  Do-It-Yourself enthusiasts often make their own inexpensive Crystalline Iodine solution.  But just like Chlorine bleach, Iodine is not effective against Cryptosporidium.  Chlorine bleach is slightly more effective than Iodine, but neither is adequate for reliably killing Cryptosporidium.

Caution:  Water that has been disinfected with Iodine should NOT be consumed by pregnant women, people with thyroid problems, or those with known hypersensitivity to Iodine.  Also, Iodine treated water should not be used continuously for more than a few weeks.

Hydrogen_Peroxide-bottleOption “D”:  Hydrogen Peroxide to Purify Water

Similar in effect to Chlorine or household bleach, Peroxide has a somewhat similar ability to purify water.  However, since Peroxide degrades very quickly, especially if the container has previously been opened, its primary benefit is that it might be available in an emergency situation when other purification methods are not.

Since the strength of Peroxide declines quickly even if the container is unopened, it is impossible to provide reliable dosing information.  Therefore, if Hydrogen Peroxide is all you have, the best option may be to dose the water with twice the amount of Peroxide than would be used for bleach, shake or stir, and then wait 30-minutes.  If there is a slight odor of Peroxide to the water, it is probably safer to drink than untreated water.  If there is no Peroxide odor for the water, repeat the process.  After the additional 30-minute wait, if there is still no Peroxide odor to the water, the treatment may not have provided a substantial purification effect.  However, the treated water will likely still be safer to drink than untreated water.  Do not drink Hydrogen Peroxide straight, even if the strength is negligible.

Specifics on Hydrogen Peroxide Water Treatment:  If one cup of water has 20 parts per million ‘bugs’ in it, the disinfectant dosage needs to be at least 20ppm but no more than 25 as more than this can produce negative health effects from chemical contamination.  If your supply of water is limited and you can’t afford to discard the over-treated water, set the uncapped container aside for several hours to let the Peroxide escape into the air.

If you have access to water testing equipment:  Peroxide dosage of 23ppm (of the active chlorine component) will show a 3ppm free residual while showing a 23ppm total chlorine level (if the background is zero). Peroxide would potentially have the advantage of breaking down to oxygen and water, but its use is also made more difficult by that fact when measuring reacted components. A quick calculation to use daily is the required dosage in parts per million, times the volume treated in gallons, divided by 120,000 (which is a constant). This calculates the number of pounds needed to give that dosage. Unfortunately there is no simple answer to dosage if you do not have access to test equipment.

Note:  The type of Iodine used for water purification tablets is not the same as the Iodine used for protection against radiation sickness.  Do not consume Chlorine or Iodine Water Purification Tablets like a pill.  For safe use, they must be properly diluted in water.

Stabilized_Liquid_Oxygen_Drops-3Bottles-4ozEa-bOption “E”:  Stabilized Liquid Oxygen (Activated Oxygen) to Purify Water

The chemicals Chlorine and Iodine both create health problems if used for an extended period of time, whereas Stabilized Oxygen has no such undesirable side effects.  An additional benefit is that Stabilized Oxygen does not adversely affect the taste of the water as do chemical treatments.

Dosage:  Use the manufacturer’s recommended dosage.  If not available, purification dosage is typically 10 – 40 drops of liquid Stabilized Oxygen for 16-ounces of clear water, shake or stir and then cap the container.  Let stand for 5-minutes before consuming.  For powders such as Katadyn Micropur and Micropur Tank Clean, use one gram of powder to treat 1-liter of water, dissolve thoroughly and then wait 5-minutes before drinking.

For short-term water storage, treat 1 gallon of already-chlorinated water by adding 10 drops of stabilized oxygen. For tap water which is to be stored long-term, add 20 drops.  For 55 gallon drums, use 55 ml or 1,100 drops.  Store stored water in a cool location, away from direct sunlight.  Keep your bottle of Stabilized Oxygen tightly capped and away from heat and sunlight.

The use of Stabilized Oxygen for water purification is a lesser-known treatment method.  It can be hard to find locally, except perhaps in health food, vitamin, or homeopathic stores.  It may be more expedient to shop for it online.  Commonly found brand names of Stabilized Oxygen are:  Aerox, Aerobic Stabilized Oxygen (formerly Aerobic 07), Aerobic Life, and Aquagen, Dynamo 2, Dexterity Health, and Genesis 1000, Katadyn Micropur.

RedWine-Camaraderie_CellarsOption “F”:  Using Wine to Purify Water

Since ancient Bible times, water was often insufficiently pure to drink untreated. By mixing 1-part red wine to 3 parts water, a limited level of purification was achieved. In modern laboratory tests, bacterium was in fact killed using this method.

In these laboratory tests, red wine ranked 3 to 4 times more effective than alcoholic beverages such as tequila. It is believed that wine is more effective due to the phenol compounds in the red wine, which are enhanced by the charred wood used in some wine-aging casks. This factor is important, and additionally noteworthy as phenol compounds may be related to the basic sulfur drugs historically used in early antibiotics. (Source: Dr. Trichopolou, British Medical Journal discussing the Greek Villager’s Diet.) The full article is here. Do not assume this method kills Giardia and Cryptosporidium, etc. View this treatment as a last-resort method which may be better than no treatment at all.

Emergency-Water-DesalinizationOption “F”:  Salt Water – Desalinization or Distillation to Make Pure Water

Do not drink saltwater.  If seawater or saltwater is your only source of water, the salt must be removed, and the water purified, before drinking it.

If you don’t have equipment designed for this purpose, this can be accomplished by boiling salt water, capturing the steam, and then letting the water condense into liquid water as the steam cools.

How To:  To accomplish this, use an oversize lid or tinfoil over the boiling pot to capture the steam, and provide a method for the steam to cool and transition back into water, and devise a plan to collect this distilled water.

Perhaps the simplest method is to extend the lid over the side of the pot, use tinfoil to direct the escaping steam, and more tin foil to form a trough to let the condensed water flow into a second, clean container.  Be sure to let the water cool before drinking.

If this is accomplished using a sterile container and sterilized tinfoil, this water is also suitable for medical use such as cleaning wounds.

Note:  Even expensive water purification filters will not remove salt from water.  Salt can only be removed by using some method to convert the water into steam, and then back again into liquid water; or, by using desalinization equipment such as found on some yachts and sailboats.

Distilled water is not healthy for long term use as drinking water.

Additional Helpful Information About Water Purification and Related Topics

Water-Filter-System-KatadynWater Purifying Filters and Devices

Advanced filtration systems capable of filtering water at the 1-micron level, can be a great alternative to the Step-2 methods described above.  Ultraviolet (UV-C) light devices for water purification, such as the SteriPEN ($70+), are also useful as they can purify 32-ounces of water in just 90 seconds.  However, since batteries are required and electronic devices are prone to damage, we do not consider Ultraviolet devices to be unsuitable as a sole source of water purification.  A SteriPEN-type ultraviolet purification device is an excellent device, but it is essential to have another method(s) available to you as a back-up.

Purification filters are far more expensive than chemical methods ($70-500), but these units are far better choice for long-term use.  Notwithstanding, even if you have a high-quality purifying filter, chemical purification methods should still be available to use as a second treatment for water which is suspected to be highly contaminated, and as a back-up to filters which can clog and mechanically operated filters which can break.

The greatest degree of safety for long-term use is provided by using a combination of a high-quality water purification filter PLUS an ultraviolet purifier.  For example, a Katadyn Pocket Water Filter ($370) PLUS either a SteriPEN Defender designed for use by the military ($129), or a SteriPEN Adventurer Opti Water Purifier with Solar Charging Case ($150).

A vendor such as REI (Recreational Equipment, Inc. – http://www.REI.com) can help you select a suitable water purification filter, such as those used for backpacking.  Since portable purification devices are very specialized and must be selected with great discernment, they will be the subject of a separate article.  Caution:  When shopping for this type of device, be sure that it is capable of removing or destroying protozoa, bacteria, and viruses.  The manufacturers of the most popular water purification filters are:  Katadyn, Sawyer, and MSR.

Look for a filter that has a pore size of 1 micron or less. This will remove microbes 1 micron or greater in diameter (Cryptosporidium, Giardia). There are two types of these filters — “absolute 1 micron” filters and “nominal 1 micron” filters but not all filters that are supposed to remove objects 1 micron or larger from water are the same. The absolute 1 micron filter will more consistently remove Cryptosporidium than a nominal filter. Some nominal 1 micron filters will allow 20% to 30% of 1 micron particles (like Cryptosporidium) to pass through.

NSF-International (NSF) does independent testing of filters to determine if they remove Cryptosporidium. To find out if a particular filter is certified to remove Cryptosporidium, you can look for the NSF trademark plus the words “cyst reduction” or “cyst removal” on the product label information. You can also contact the NSF at 789 N. Dixboro Road, Ann Arbor, MI 48113 USA, toll free 800-673-8010 or 888-99-SAFER, or visit their website:  www.nsf.org/certified/DWTU/. At their Website, you can enter the model number of the unit you intend to buy to see if it is on their certified list, or you can look under the section entitled “Reduction claims for drinking water treatment units – Health Effects” and check the box in front of the words “Cyst Reduction.” This will display a list of filters tested for their ability to remove Cryptosporidium.

Because NSF testing is expensive and voluntary, some filters that may work against Cryptosporidium have not been NSF-tested. If you chose to use a product not NSF-certified, select those technologies more likely to reduce Cryptosporidium, including filters with reverse osmosis and those that have an absolute pore size of 1 micron or smaller.

Crypto-Parasite-02Cryptosporidium, aka “Crypto”

Cryptosporidium is a microscopic parasite that causes the diarrheal disease cryptosporidiosis. Both the parasite and the disease are commonly known as “Crypto.”

There are many species of Cryptosporidium that infect humans and animals. The parasite is protected by an outer shell that allows it to survive outside the body for long periods of time and makes it very tolerant to chlorine and iodine disinfection.

While this parasite can be spread in several different ways, drinking water and recreational water are the most common method of transmission. Cryptosporidium is one of the most frequent causes of waterborne disease among humans in the United States.

Reverse osmosis water treatment and water purification filters which are labeled as providing “absolute 1-micron” filtration are the only reliable consumer-level methods for minimizing the risk of Cryptosporidium contamination.

Water-Heater-Drain_edited-1Often Forgotten Sources of Water Which Are Inside Your Home or Office

Sources of reasonably-clean water within a home are your water heater, ice in the refrigerator, swimming pools, fish tanks, and your water pipes (if you have turned-off the water at the point where it enters the house).  Once the outside water has been turned off, put a clean container under the lowest water faucet in the house (basement, if you have one), and open that faucet.  Then, go to the highest water faucet (top floor, or a physically higher faucet if it is a 1-story house, and open that faucet to eliminate the natural vacuum which exists within your plumbing system.  Any remaining water in the pipes should immediately start draining into the container.  Return to the low faucet and switch containers as needed, or be prepared to turn off the faucet so that you don’t waste water. Toilet tanks also store water, but are unreliable in regard to water quality, but this might also be a source of water that can be used for the purification process.

Soft_DrinksSoft Drinks, Carbonated Beverages, Fruit Juice, Alcoholic Beverages, and Other Canned or Bottled Drinks

Soft drinks, flavored and sugar drinks, and those containing caffeine, can be counterproductive in an emergency situation.  Drinks labeled as containing salt or sodium chloride, can increase thirst.  Liquid Gatorade and sports drinks can be useful, but may upset the body’s electrolyte balance if consumed in quantity.  These liquid sports drinks may also bring on nausea or an upset stomach if consumed in combination with foods not usually eaten, or when the stomach is empty.

Gatorade-Powder-bImproving the Taste of Chemically Treated Water (By Masking)

Powdered Gatorade “Thirst Quencher”: The powdered sport drink Gatorade is useful for masking the taste of water treated with Chlorine or Iodine, as well as for restoring the body’s electrolyte balance after a prolonged period of strenuous exertion, heavy sweating, or an extended time in a high heat environment. When used simply to improve the taste of purified water, use ¼ strength, or just enough to distract you from the unpleasant taste of the water.  Improving the taste of treated water can be particularly important with children who may not drink sufficient water to maintain health because they don’t like the water’s strange taste.

Water-TasteImproving the Taste of Chemically Treated Water (By Treatment)

Anti-Chlorine and Stabilized Oxygen:  Packaged under a number of different names, anti-Chlorine treatments and Stabilized Oxygen can be used to neutralize residual chlorine which remains in the water.  However, since these additives remove the Chlorine and its beneficial ongoing purification properties, it is best to use anti-Chlorine treatments just prior to drinking the water.  Since Liquid Oxygen and Activated Oxygen powder purity water, these can be used to improve the taste of stored water.  Commonly found brands:  Katadyn Micropur Antichlor MA and Potable Aqua PA-Plus Neutralizing Tablets.

Contaminated-PondRadiation, Heavy Metals, Farm Chemicals, and Manufacturing Waste in Water

If your water source is contaminated with radiation or heavy metals you will not be able to clean it using these cleaning and purification methods.  However, these methods will still be helpful, particularly if the source of water has set undisturbed for several days.  (Some of these contaminates will settle to the bottom of the container, so if this type of contamination is a concern, carefully remove the surface water so that contaminates at the bottom of the container are not re-mixed with the water.

Shelf Life of Water Purification Products

When stored at room temperature:  Bleach in a sealed container has a shelf life of 1-year.  Chlorine and iodine tablets have a shelf life of 4-years if unopened, 1-year if the contents has been exposed to the air.  Water which has been chlorinated according to the above storage method has a shelf life of up to 1-year if stored in the dark or in a container impervious to light.  The effective life of filters depends primarily on the clarity of the water being filtered.  If water is pre-filtered until it is clear, most purification filters will last for several years of modest use.  Be sure to read the manufacturer’s instructions, and purchase additional filter elements if extended use is anticipated.

Expiration Dates:  Unfortunately, Chlorine and Iodine tablets are not required to have an expiration date, so these products should be purchased direct from the manufacturer, or from a trusted retailer which turns over its inventory quickly.  Some manufacturers, such as Potable Aqua, print a code on the bottle which they use to track the manufacturing date and lot number.  You can use this code to decipher the age of the product.  For example, Potable Aqua code:   1 13 01

The code is generally a five or six digit number. The first digit(s) represent the month of manufacture. The next two digits represent a two-digit year, and the last digits represent a batch number for that month and year. Using the code example above, the product was manufactured the 1st month of the year 2013 and was the 1st batch of product made that year.

If in the field, check the tablets appearance to determine if they are still effective. If the tablets are gray or dark brown in color, they are likely still effective. If they are light green or yellow, they are probably not effective. If you have no other method for purification, use 2-4x the standard dosage.  If the treated water has an unusually strong odor after adding the tablets, discard the water and try again using fewer tablets.

Water-Tanks_ArrayTreating Tap Water or Pure Water for Storage

Be sure that the water you are treating is drinking-quality water to begin with. To treat water for storage, use liquid household chlorine bleach that contains 5.25 percent sodium hypochlorite. Do not use bleach with soaps or scents added. Add the bleach according to the table below, using a clean, uncontaminated medicine dropper.

 4 drops bleach per quart or liter container of water
 8 drops bleach per 2-quart, 2-liter, or ½ gallon container of water
 16 drops bleach, or 1/4 teaspoon, per gallon or 4-liter container of water

When treating larger quantities of water, use the following table to convert drops to standard measuring units.

  8 drops = 1/8 teaspoon
 16 drops = 1/4 teaspoon
 32 drops = ½ teaspoon
 64 drops = 1 teaspoon
 192 drops = 1 Tablespoon
 384 drops = 1/8 cup which is equal to 2 Tablespoons

Stir the water and allow it to stand for 30 minutes. Chlorine should be detectable by odor after the 30 minute waiting period. If the water does not smell like chlorine at that point, repeat the dose and let it stand another 15 minutes. Place caps on containers and attach labels describing the contents and when each was prepared.

Water stored in metal containers should not be treated, prior to storage, with chlorine since the chlorine compound is corrosive to most metals. Therefore, only very pure water should be stored in metal containers.

Water-Barrels-2Water Storage in 55-gallon Drums & Storage Tanks

If you intend to utilize 55-gallon drums for water storage, first be sure that they are food-grade plastic or metal containers with a food-grade liner or treatment.  If purchased as a previously used product, make sure that the container has not been used for something other than food, and that the contents did not contain a food product which will transmit flavor, odor, or otherwise taint your water.  Suitable “used” containers can often be purchased for $20-50 from a local bottler of Coca Cola or Pepsi products.

Liquid or powder Chlorine, such as obtained from a swimming pool supply store can be used to purify water, but the dosage is far different from that which is listed above for purifying water using household bleach.  Since different Chlorine products contain this chemical in various strengths, you need to check with a knowledgeable source for specific recommendations.  For water storage in drums and tanks, a “test kit” is essential.  Your local water authority, or even a knowledgeable pool supply owner, can help you select the best chemicals and test equipment for treating and testing drinking water.  Fortunately, these items are relatively inexpensive.

Click Here to download a flier containing instructions for “Katadyn Mircobox”, a simple water treatment method for 55-gallon drums and small water tanks.  http://katadynch.vs31.snowflakehosting.ch/fileadmin/user_upload/katadyn_products/Downloads/3-step_Flyer_Microbox_English.pdf

Additional Warnings:

  • Crystalline iodine 4-8 grams used in a stock solution constitutes a human lethal dose if accidentally swallowed in a single dose. Keep this and all chemicals out of the reach of children.
  • Water that has been disinfected with iodine is NOT recommended for pregnant women, people with thyroid problems, those with known hypersensitivity to iodine, or continuous use for more than a few weeks at a time.


Though we believe that the information contained here is accurate, it is only a compilation of information assembled from sources we believe to be reliable.  This is not medical advice, and it is your responsibility to validate the accuracy of any information used.  Below you will find links to sources which we have used, which might also be of value to you.

Bibliography (Partial List of Resources Used):

U.S. Center for Disease Control

Source:  http://www.cdc.gov/healthywater/drinking/travel/emergency_disinfection.html

Source:  http://www.cdc.gov /travel/page/water-treatment.htm

Source:  http://wwwnc.cdc.gov/travel/page/water-treatment.htm

U.S. Federal Emergency Management Agency (FEMA)

Source:  http://www.ready.gov/managing-water

Source:  http://www.fema.gov/pte/foodwtr.htm

U.S. Environmental Protection Agency (EPA)

Source: http://water.epa.gov/drink/emerprep/emergencydisinfection.cfm

Red Cross

Source:  http://www.redcross.org/prepare/disaster/water-safety/water-treatment

Source:  http://www.clorox.com/products/clorox-concentrated-regular-bleach/faq/

King County Public Health Department, Washington State

Source:  http://www.kingcounty.gov/healthservices/health/preparedness/disaster/SafeWater.aspx

Source: http://www.doh.wa.gov/Emergencies/EmergencyPreparednessandResponse/Factsheets/WaterPurification.aspx

USA Today

Source:  http://traveltips.usatoday.com/long-boil-water-purification-62933.html

Survival Blog

Source:  http://survivalblog.org/water-purification-with-household-bleach/

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