WATER
Challenge
Heavy rains have flooded the nearby water treatment facility, introducing two dangerous pathogens (Giardia and Shigella) into the water supply. Local authorities have issued an order to use bottled water or boil all tap water. The rains are expected to continue for the next five days. How will you provide clean drinking water for your family? Do you understand the risks that these pathogens pose?
Never underestimate the importance of having clean, drinkable water. A useful saying is that humans can live three minutes without air, three days without water, and three weeks without food. Given that air quality is often not a problem in many disasters, it leaves water as the primary need—certainly much more important than food for short-term survival. Also, take a moment to consider that even in the best of times, over a billion people on this planet don't have access to clean drinking water.46
There are two approaches to making sure that you have water in a crisis. You can either maintain a permanent stockpile of water, or you can have empty containers ready to fill when a disaster is approaching. The obvious advantage of the permanent stockpile is that you are always ready. The disadvantage is that water is heavy, bulky, and can be a mess if not handled correctly. Also, unless treated with a water preserver, it must be poured out and refilled about every six months—see “Storing Water” further in this chapter.
Regardless of your approach, one thing holds true. If a disaster is imminent, store as much water as possible. If you don't have enough water containers, then fill bathtubs, buckets, pots, barrels, and anything else you have available. Remember that water is not only used for drinking, but also hygiene and sanitation. Don't neglect to account for those needs. As discussed in Chapter 2, many of the worst bacteria-related illnesses are a result of fecal-oral contamination. Keeping yourself and your environment clean is extremely important in times of crisis.
Finally, don't forget to account for your pets. If you have a couple of cats, they probably won't have much impact on your water consumption. However, if you have two German Shepherds, three cats, and a donkey, you should definitely determine their water usage and budget accordingly!
Sun-Mar composting toilet
When water is in short supply, the toilet is going to be your biggest enemy. The amount of non-potable water (i.e., water not fit for drinking) needed depends on how old your toilet is, and how frugal you are with your flushes. If your toilet was made prior to 1982, it probably takes 5 to 7 gallons per flush. That is a lot of water. Newer toilets require only about 2 to 3 gallons per flush. This conservation is an excellent reason to upgrade at least one toilet if you happen to live in an older home. If your budget doesn't allow the upgrade, consider putting a few heavy glass jars or bottles in the tank to displace some of the water—thereby reducing the amount used with each flush.
When city water is no longer available, there are four obvious choices for sanitation:
1. Dig a hole or trench outdoors—this can get old in a hurry, as well as be a source of disease.
2. Use a potty bucket with disposable liners—smelly but manageable with the correct supplies.
3. Use a self-contained composting toilet—an excellent, but expensive, alternative (see www.lehmans.com).
4. Ration your water, and continue to use your conventional toilet—the least impact to your family, but one that requires access to a significant amount of water.
If you opt to use your toilet, you will need to store, or have access to, enough non-potable water for at least one flush per person per day. The idea is to flush the toilet only after bowel movements. A great way to remember this is to keep in mind the saying, “If it's yellow, let it mellow. If it's brown, flush it down.” A tad vulgar perhaps, but you won't forget it.
There are two ways to flush a toilet when water has been disconnected. The first is to cut off the incoming water valve (usually just behind the toilet), pour water into the back of the tank, and flush as usual. This works fine, but can be a little messy. The second method is to pour the water directly into the bowl. If unfamiliar with plumbing, you might think that the toilet would overflow. However, as the water level rises, a partial vacuum is created as water spills over the dam in the back of the toilet boil. This vacuum pulls the water out of the bowl and down into the sewage pipe.
One final note about operating toilets with external water sources: once you are finished flushing, add a little water to the toilet bowl. If the water level is too low, it will allow sewer gas to enter the home.
One other topic that fits in the category of sanitation is sewage backflow. Your sewer or septic system is designed to remove sewage from your home, but that same piping can inadvertently bring sewage back up into your home. This most frequently occurs when flood water flows into the sewer system and floats raw sewage up through a home's toilets, tubs, and sinks—disgusting to be sure!
Install a backflow valve to prevent sewage from backing up into your home from flooded sewage systems.
The surest way to prevent sewage back-flow is to install a backflow valve on your sewage line. The backflow valve allows sewage to flow in only one direction—that is, out of your home and not back into it. If you are a handyman with a bit of plumbing experience, you can probably do this job yourself. Otherwise, contact your local plumber. If possible, have the backflow valve installed somewhere convenient to access. This way, if you ever have a clog associated with the backflow valve, you can easily clear it.
This might be a good place to emphasize the importance of maintaining good personal hygiene during times of crisis. Simply put, you must keep your hands clean of fecal matter and other contaminants. Many serious infections, including salmonellosis and E. coli, can be the result of contamination from tiny amounts of fecal matter entering your body through the mouth, nose, or eyes. These bacterial infections can be especially deadly when access to medical care is limited.
When you use the toilet, or touch anything else that might be contaminated (e.g., a sick person, garbage can, raw meat), you must wash your hands thoroughly. Likewise, before handling food, you should always assume your hands are dirty and wash them. For these reasons, budget a gallon of water for hygiene per person per day. This recommendation exceeds those of many other DP books, but hygiene is critical to preventing illness and should not be shortchanged.
Washing has one primary goal; to remove the contaminants from your skin. The soap foam bonds to the contaminants, and water rinses them away. Teach your children the proper way to wash their hands (see tip box).47
Washing Hands
1. Use warm water if possible.
2. Lather soap into a thick foam.
3. Scrub hands thoroughly for at least twenty seconds.
4. Rinse thoroughly.
5. Air dry, or use a disposable towel.
6. Use towel to turn off faucet.
Hand sanitizers with 60 percent or more alcohol are an excellent alternative to hand washing when water is not available. They do a great job of killing pathogens but don't remove waste, blood, or dirt from your skin. As with soap and water, most sanitizers don't provide extended protection. They only kill what is currently on your hands. There are a few lotion-based sanitizers that claim to provide several hours of protection, but it is not clear that they are an adequate substitute for periodic hand washing.
Disposable baby wipes can also be used to clean your hands and body, but most wipes are not alcohol-based and don't clean as well as soap and water. Using larger, disposable bathing wipes can be an excellent temporary replacement for taking showers or baths. Campers have used bathing wipes for years, and they can really help you to feel refreshed.
It is also a good idea to have plenty of heavy-duty garbage bags and twist ties on hand. Plastic bags are handy for getting rid of food remnants, medical waste, and contaminated clothing. They can also be used to seal leaks, gather water, serve as a rain poncho, act as a toilet, and much more.
Homemade Disinfectants
1 part bleach to 9 parts water
or
hydrogen peroxide + vinegar applied separately
Finally, if you need to clean a hard surface, such as a countertop, door knob, or toilet, and are out of Lysol or other germ-killing cleansers, you can call upon bleach to serve as a powerful disinfectant. Simply mix 1 part bleach to 9 parts water.48 Just be careful not to spill the mixture on carpet or clothing since it will cause whitening. If the surface will later be used for preparing foods, it should be rinsed first with clean water.
An alternative to using bleach is to spray the infected surface with 3 percent hydrogen peroxide (i.e., the standard drug store concentration), and then again with white vinegar. This combination has been shown effective at killing E. coli, Salmonella, and Shigella, and is safe to use without additional rinsing.49 Don't combine the vinegar and hydrogen peroxide in the same bottle. Also, keep the hydrogen peroxide in an opaque bottle since light will degrade the solution.
To determine your family's daily water needs, simply add up the water required for drinking (1 gallon per person), hygiene (1 gallon per person), and sanitation (2 to 7 gallons per person depending on your toilet type). Drinking and hygiene needs must be met with potable water, but sanitation can be handled with non-potable water. It is recommended that you store (or have access to) enough water to support your family for a minimum of fourteen days.
For a family of five, this corresponds to: 5 people × 2 gallons per day × 14 days = 140 gallons of potable water. And if toilets are to be used (assuming 3 gallons per flush): 5 people × 3 gallons per day × 14 days = 210 gallons of non-potable water.
It should go without saying that storing 350 gallons of water is something that requires prior planning. If you are fortunate enough to have access to a large body of water, such as a swimming pool, stream, or lake, you can draw upon it for your non-potable needs. Using outside sources like these significantly reduces your storage requirements.
The average American uses about 100 gallons of water per day.
The average American household uses about 94,000 gallons of water each year.50 Using the 2000 Census estimate of 2.59 people per household, this consumption figure converts to about 100 gallons per person per day! Compare this to the 5 gallons of water recommended per person (2 gallons of potable, 3 gallons of non-potable). Suffice it to say, your family should be prepared to live on much less water than they are accustomed to. The days of lounging in the hot shower will be a thing of the past.
The shelf life of water is difficult to predict because it is based on many factors, including the purity of the source, storage temperature, lighting, and type of storage container. In some conditions, water can be stored safely for several years, while in others, it can become contaminated in a matter of months. Follow the water storage guidelines (in tip box) for achieving the best shelf life.
Water Storage Guidelines
Use FDA-approved DOT #34 opaque containers
Store out of light
Keep away from pesticides, gasoline, paint, or chemicals
Store where it won't freeze
Cycle every six months unless treated with a water preserver
Pre-treat if it comes from untreated sources (e.g., well)
Water storage containers (courtesy of Baytec and Reliance Products)
It is a good idea to have both large and small containers for your water storage. The large containers are efficient at storing sizable quantities of water in a small space. But if you are forced to relocate, or simply have to go out in search of additional water, you will need containers light enough to transport. A gallon of water weighs approximately eight pounds, so portable containers shouldn't be over about six gallons in size (less if you are unable to handle 50 pounds). Keep two sets of portable containers. Use one set for retrieving potable water and the second set for retrieving non-potable water. By keeping them separate, you eliminate the risk of cross-contaminating your containers.
Prepare your potable water containers in advance of any disaster. Containers should be cleaned following these simple steps:
1. Mix 1 tablespoon of unscented liquid household bleach (i.e., 5–6 percent sodium hypochlorite) into one gallon of water.
2. Pour the solution into the container, rubbing or brushing it on the threads and mouth.
3. Shake it around in the container, and then let it sit for ten minutes.
4. Rinse the container thoroughly with clean water.
Unscented household bleach can also be used to pre-treat water prior to storage by adding 4 drops per gallon and mixing well. However, pre-treating water with bleach is only recommended if the water comes from an untreated source, such as a well or rural township water. Most cities pre-treat their water before it is piped to customers, so further pre-treating is unnecessary and won't increase the shelf life of the water. Additional pre-treating won't cause any harm, but it may leave an unpleasant odor and taste.
Water can be pre-treated with 4 drops of bleach per gallon of water.
Commercial concentrated water preservers, such as 7C's Safety & Environmental's Water Preserver, can be added to water to significantly increase the shelf life. These products are made of stabilized sodium hypochlorite, which is designed to prevent microorganisms for a minimum of five years. If you have large water storage containers (e.g., 55-gallon drums, 250-gallon Super Tankers), then using a water preserver makes sense. However, if you are just using jerry cans or smaller containers, it isn't difficult to simply cycle your water every six months.
Courtesy of 7C's Safety & Environmental, Inc.
The Environmental Protection Agency (EPA) has estimated that 90 percent of the world's fresh water is contaminated and unsuitable for drinking without some form of purification.50 The days of kneeling down on a hike and sipping from the stream are long gone. Don't make the mistake of thinking that just because water looks clear or tastes good that it is free of contaminants. That includes frozen water, which can house hepatitis A, Salmonella, and Cryptosporidium for months.51 The CDC estimates that 88 percent of the world's cases of diarrhea are the result of unsafe water, inadequate sanitation, and poor hygiene. Water-related illnesses rank as one of our planet's deadliest killers, resulting in the death of 1.5 million people annually, most of them children.52
The EPA classifies water contaminants into six categories (see tip box). Based on these categories, the agency publishes a long list of contaminants and sets their maximum allowed levels in drinking water.53 Likewise, the National Sanitation Foundation International (NSF) certifies that water filters remove those contaminants to a specified level of effectiveness. Contaminant removal is tested by adding an in-fluent and then measuring the effluent. In other words, they start with clean water, add a contaminant, pass the water through a filter and see how much of the contaminant has been removed. For a filter to be certified as effective against a contaminant, it must meet or exceed the NSF requirements.54
Water Contaminants
Pathogens
Organic chemicals
Inorganic chemicals
Disinfectants
Disinfection by-products
Radionuclides
It is instructive to compare the EPA safe-water requirements to the list of contaminants removed by NSF-certified water filters. For example, the EPA requirements dictate that drinking water contain less than 0.015 mg/L of lead, and the NSF certification process requires that water contaminated with 0.15 mg/L of lead be reduced down to a maximum of 0.01 mg/L (about 93 percent removal)—just within the EPA limit. It becomes clear that EPA requirements and NSF certification align closely to first dictate, and then test, water quality.
Pathogens are microscopic organisms that include protozoa, bacteria, parasitic worms, fungi, and viruses.55 They can generally be classified into one of three broad categories: parasites, bacteria, and viruses. For detailed information about many different water contaminants, see the Center for Disease Control and Prevention's online listing.56
Pathogens are classified as parasites, bacteria, and viruses.
Parasites include worms, lice, and protozoa. All can be transmitted through water, but for modern societies, protozoa represent the greatest waterborne parasitic threat. Protozoa are single-celled organisms that may have more than one nucleus. They are generally found in water as microbial cysts and cause serious gastrointestinal illness when ingested. Their source is human or animal fecal waste, and they typically range from 2 to 30 microns in size. A micron (a.k.a., micrometer) is 1/1,000,000 of a meter. Fortunately, parasites of this size are large enough to be easily removed by quality water filters (i.e., those with an absolute pore size of less than 1 micron).
Giardia (CDC photo)
Bacteria are single-celled microorganisms without a nucleus, generally measuring from 0.2 to 4 microns in size. They are found in every habitat; growing in soil, seawater and fresh water, and even deep in the Earth's crust. Many bacteria are not harmful, and some are even beneficial to your health. There are approximately 40 million bacterial cells in a gram of soil and 5 million in a single teaspoon of fresh water.57
Some of the bacteria found in water are the result of transfer from fecal waste. As with parasites, ingestion usually results in severe gastrointestinal illness, along with other associated infections. Larger bacteria are effectively removed by conventional water filters, while other smaller bacteria are more difficult to remove.
Salmonella (CDC photo)
Viruses are essentially raw genetic material with a protective coating called a capsid. They infect healthy cells and inject their genetic characteristics into them. In turn, those contaminated cells quickly replicate. Consuming virus-contaminated water can cause gastrointestinal illness, weakness, fever, liver disease, and paralysis. Viruses are very small in size, measuring from 0.004 to 0.3 microns in size. Because of their tiny size, most water filters will not effectively remove viruses. However, there are a few filters that do remove them by taking advantage of the fact that viruses will attach to larger particles under certain conditions.
Hepatitis A (CDC photo)
For a conventional filter to effectively remove a contaminant of any type, the absolute (not average) pore size of the filter membrane must be smaller than the contaminant. Table 3-1 provides a quick comparison of general filter requirements to remove several common pathogens.
Depending on where you look, you will find conflicting data regarding the size of different microorganisms. That's because the micro organisms can be many different sizes depending on the conditions in which they grow. How then do you decide if a filter will remove a particular pathogen? The best way is to review the test data for the specific filter in question. Certified filters will provide performance information such as “removes 99.99 percent of Cryptosporidium.” Much more information about selecting a water filter is given later in this chapter.
Table 3-1 Filter Absolute Pore Size Recommendations
Microorganism Type |
Microorganism |
Recommended Absolute Filter Pore Size (microns) |
Protozoa |
Giardia lamblia |
|
Cryptosporidium |
1 |
|
Entamoeba histolytica |
||
Bacteria |
Escherichia coli |
|
Vibrio cholera |
||
Shigella |
0.2–0.4 |
|
Campylobacter |
||
Salmonella |
||
Virus |
Hepatitis A |
|
Norovirus |
|
|
Poliovirus |
N/A—see note |
|
Rhinovirus |
|
Note: Due to the very small size of viruses, most filters don't adequately remove them. However, there are a few exceptions, as noted later in the chapter.
The EPA tests drinking water for a long list of organic and inorganic chemicals.53 These include chemicals discharged from various types of factories (e.g., petroleum, plastic, metal, coal-burning, pulp), runoff from herbicide treatments, corrosion from plumbing, and erosion of natural deposits. Consumption of chemical contaminants can cause cancer as well as damage to the body's basic systems and organs.
Most conventional membrane filters do a poor job of removing chemicals. However, distillation and reverse osmosis systems have been shown to be effective treatment methods.
Distillation and reverse osmosis are the best ways of removing chemical contaminants.
Disinfectants are chemicals added to water during the purification process to kill microbes. These additives include chloramines, chlorine, and chlorine dioxide. By-products created by the water treatment process include bromate, chlorite, haloacetic acids, and total trihalomethanes. Consuming high levels of these increases the risk of cancer as well as liver, kidney, and neurological disorders.
Fortunately, these additives and by-products are often able to be removed with a quality, carbon-based water filter.
Drinking water in the United States has very low levels of radioactive contamination (a.k.a., radionuclides). Most of what is present in water occurs naturally as result of erosion of natural deposits of certain minerals. Radioactive contamination can also be the result of the introduction of human-made nuclear materials, such as from an accidental spill or improper disposal practices. Examples of radioactive contamination include alpha/beta particles, uranium, and radium 226/228. Long-term exposure to high levels of radionuclides in drinking water causes an increased risk of cancer. Exposure to uranium in drinking water also causes kidney damage.58
Conventional membrane filters will not remove radionuclides. Three methods that have been shown to reduce radionuclides are: ion exchange devices used to remove water hardness, reverse osmosis systems, and lime softening.59
If you are interested in learning about the levels of contaminants in your local water supply, go to the EPA's website, www.epa.gov/safewater, and find the link for your area. If your water provider doesn't post its findings on the EPA website, you may have to contact your provider directly. It is both informative and well advised to understand the water quality issues facing your community.60
Investigate your water quality at www.epa.gov/safewater.
Even in the best of times, maintaining the purity of your drinking water requires careful attention. You may find that your local drinking water falls short of EPA guidelines. During disasters, water quality can quickly degrade, or worse, can be completely shut off. To adequately prepare for contamination or shortage, you will need a well thought-out water management plan.
Unless you have a large storage tank of clean drinking water, or can draw water from an uncontaminated source, such as an underground well, you will likely need some method of purifying water from non-potable sources. Let's start by quickly examining the water purification process that large treatment facilities use.
The purification process consists of six fundamental steps:61
• pre-treatment—screen to remove large debris, and perform limited softening and chlorination
Water treatment facility (photo by FEMA/Manny Broussard)
• pH adjustment—adjust alkaline/acidic level
• coagulation/flocculation/sedimentation—clarify to remove particles
• filtration—remove smaller particles
• disinfection—kill pathogens using chemicals and UV light
• additional treatments—fluoridate, hard/soft condition, and remove radium
Strict replication of these steps on a small scale is not practical. However, the basic goals of purification still apply—remove the debris and kill or remove the impurities. Unfortunately, there is a great deal of misinformation about how to make non-potable water safe. Even within the DP community, confusion abounds. The information presented here will make clear the efficacy of different methods.
Purifying Water
Boiling
Filtering/purifying
Chemical disinfection
Distillation
Reverse osmosis
Ultraviolet light
There are six primary techniques that can be used independently or in conjunction to purify water (see tip box). Each method has its respective advantages and disadvantages. Let's begin with a discussion of each of the various techniques, followed by several recommended approaches to purifying water.
Boiling is the optimal way of killing microorganisms. It is simple and effective at neutralizing all types of pathogens, but it will not improve the taste of water. Nor will it remove particulates or chemical impurities. Tests have shown that microorganisms are destroyed by the time water reaches the boiling point (212°F). Boiling the water for extended durations (e.g., ten to thirty minutes) as suggested in some texts is unnecessary.50 The generally accepted guidance is to bring the water to a rolling boil for one minute. After that, let the water cool naturally, providing a final measure of safety by ensuring that the water remains at high temperatures for an extended time.
Boiling is an excellent method of purifying already clear water, such as tap water, that has become infected with a pathogen. The main drawback is that it is slow and requires a heat source. Boiling is also not optimal for purifying water from natural sources, such as a lake, since it doesn't remove any particulates or debris and won't improve the taste.
Filtering can be as simple as passing water through a handkerchief, or as sophisticated as forcing it through a nearly solid substance that allows little else but water molecules to pass through. Water coming from natural sources, such as a lake or river, is often filtered in stages—a coarse filter first to remove the dirt and debris, followed by a much finer filter to remove pathogens. The idea is to get as much crud out of the water as possible before trying to purify it. This approach greatly helps to prevent clogging of the filter.
Purifiers are the cream of the water filter crop—able to reduce all types of pathogens to safe levels.
The terms filter and purifier are often used interchangeably by retailers, even though they refer to very different things. Filter is a general term describing any device that can be used to remove contaminants from water. This could be as crude as a simple coffee filter, although typically it refers to a device that contains some sort of fine membrane. Most general purpose water filters remove protozoa and select bacteria. Contrary to popular belief, they do not remove minerals, heavy metals, or salt.
A water purifier is a special type of filter, one with a very specific definition. The EPA defines a purifier as something that reduces all pathogens to safe levels—exceeding log-6 protection for bacteria (99.9999 percent removed), log-3 for Cryptosporidium (99.9 percent removed), and log-4 for viruses (99.99 percent removed).62 When you see something described as a “certified purifier,” you should recognize that the device offers broad protection from waterborne contaminants.
Water filters can be grouped into one of three categories: point-of-entry (POE), point-of-use (POU), and portable. A POE filter attaches to the main water line, filtering water throughout the entire house. A POU filter sits on the countertop or under the sink and filters only a single tap. Finally, portable units are lightweight pump-driven or gravity-fed devices often used when camping or traveling. Pitchers and other filtered dispensers can also be categorized as portable units.
Having a quality POU or POE filtering system will ensure that you can very likely continue to use your city's water even if it becomes contaminated. This provision relieves the burden of trying to find clean or treated water. Having a POU or POE filter obviously does not help in the event that water service is completely shut off. For those situations, you will need to locate an alternate water source, and use a pump-driven or gravity-fed water filter as necessary.
Katadyn's Pocket filter
Whether choosing a POU or POE system, select one with an absolute pore size of 1 micron or smaller. This rating indicates that the filter will not pass anything larger than 1 micron in size. A filter with 1 micron absolute pore size will safely remove all protozoa (e.g., Cryptosporidium and Giardia) and provide some protection from bacteria (e.g., E. coli and Salmonella). However, it is unlikely that the filter will protect you from viruses since they are significantly smaller than 1 micron.
Fortunately, there are a few select water filters that have been independently verified to eliminate all forms of pathogens (i.e., bacteria, protozoa, and viruses) without the use of chemical disinfectants. These filters are classified as true water purifiers, and offer a simple one step process to removing pathogens (discussed in “Selecting a Water Filter”).
Polar pure
Two widely used halogen chemicals for killing water-borne pathogens are iodine and chlorine (along with their respective derivatives). Popular products include Micropur MP1 chlorine dioxide tablets and Potable Aqua's titratable iodine tablets. These tablets are easy to use and have shelf lives of at least four years if unopened—one year if opened.63,64Another product, Polar Pure iodine crystals, is a little more difficult to precisely administer but is much less expensive and offers the advantage of having a nearly indefinite shelf life.65
MSR's MIOX
If you have no other means, you can use household bleach or 2 percent tincture of iodine to disinfect water. These products are as effective as the commercial chemical water disinfectant products (e.g., MP1), but not as convenient to use. Also, bleach has a much shorter shelf life—requiring replacement every six months to maintain potency.66
Halogen disinfectants (a.k.a., electronegative chemicals) of this type are considered effective against bacteria, somewhat effective against viruses, and of limited value against protozoa. The reason for this limitation is that protozoa cysts have protective coatings around them. Cryptosporidium in particular is resistant to halogen treatment.67
Finally, there is one device (Mountain Safety Research's MIOX) that uses salt, water, and electricity to create a foamy brine of oxidizing agents. When added to water, the brine will neutralize protozoa, bacteria, and viruses. Disposable test strips are used to verify that the water has been adequately treated. Independent tests have shown MIOX meets the EPA Guide Standard and Protocol for Testing Microbiological Water Purifiers (a.k.a., EPA Guide Standard).68 Suffice it to say that this level of purification is exceptional—far better than iodine or chlorine. One noticeable disadvantage of the mixed oxidant method is that it requires a four-hour treatment time for Cryptosporidium.
Chemical Disinfection
1. Add halogen per Table 3-2.
2. Mix the water thoroughly.
3. Splash the disinfected water onto the container's threads.
4. Wait thirty minutes. Increase the wait time to two hours for very cold water.
If using commercial chemical disinfectants, such as Polar Pure or Micropur MP1, the dosages are clearly marked on the package. However, if you are using bleach or iodine to disinfect water, you will need to measure your own dose.
Table 3-2 gives the recommended dosages for disinfecting clear and cloudy water using bleach or iodine. The recommended dose for bleach is 2 drops per quart of water, which translates to approximately 5–6 parts per million (assuming a bleach solution with 5–6 percent sodium hypochlorite). Similarly, the recommended dose for iodine is 5 drops per quart of water, corresponding to approximately 5 parts per million (assuming a 2 percent tincture of iodine solution). After treating with either chemical, let the water sit covered for thirty minutes, giving time for the halogen to work. Treated water should have a detectable chlorine or iodine odor.
Table 3-2 Ratios for Purifying Water with Bleach or Iodine.69,70
Water Quantity |
Clear Water |
Cloudy Water |
1 Quart/Liter |
Bleach - 2 drops |
Bleach - 4 drops |
1 Gallon |
Bleach - 8 drops (⅛ tsp) |
Bleach - 16 drops (¼ tsp) |
5 Gallons |
Bleach - ½ tsp |
Bleach - 1 tsp |
10 Gallons |
Bleach - 1 tsp |
Bleach - 2 tsp |
55 Gallons |
Bleach - 5½ tsp |
Bleach - 11 tsp |
Notes:
1. 1 drop = 0.05 mL
2. 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.71
In general, the more turbid the water, the more disinfectant you need to add.72 Consequently, most references suggest doubling the concentration for cloudy water—as indicated in Table 3-2. Although effective, the increased dose introduces a strong chemical taste. An alternative approach is to filter the water first to clear it up, and then use the standard dose of halogen. A second alternative is to double the dose of disinfectant and then filter using a small-pore filter to remove some, although not all, of the unpleasant chemical taste.
The taste of chemically-treated water can be especially objectionable to children.
Very cold water (i.e., water below 40°F) slows the reaction time of the halogen, leading to the suggestion once again to double the normal dose of disinfectant. An alternative to this is to allow the water to warm before treating it. A second alternative is to permit the halogen to work for two hours instead of thirty minutes when disinfecting very cold water.73
One drawback of using chemical disinfectants is the objectionable smell and taste of the treated water. There are several things that can help with this:
• Avoid using higher doses by first clarifying the water or allowing the disinfectant to work longer.
• Use a filter subsequent to the chemical disinfection process.
• Mix in a powdered fruit drink mix, such as lemonade or Kool-aid, that contains ascorbic acid (vitamin C). The ascorbic acid helps convert the chlorine and iodine to tasteless chloride and iodide.
• Allow the treated water to air out for a couple hours before drinking.
If you plan to use a chemical disinfectant, it is advisable to try out several methods to determine which yields the best-tasting solution for your family.
Personal aside: In a very unscientific taste test of chemical treatment methods, my own family concluded that iodine-treated water was by far the worst smelling and tasting, bleach-treated was second, MIOX-treated water third, and water treated with Micropur MP1 ready-to-use tablets was the least objectionable.
Distillation is a process of boiling water and then collecting the water vapor as it condenses. This method of purifying water is extremely effective at removing all types of pathogens (i.e., bacteria, protozoa, and viruses). Distillation and reverse osmosis are also the only methods discussed that do an excellent job of removing chemical contaminants.74
Water distillation system (courtesy of Nutriteam)
A disadvantage of using distillers is that they are slow, typically taking about six hours to yield one gallon of water. They also require electricity to operate, which given the amount of time they have to run, might be a significant problem during many disasters.
Osmosis is the process of flowing from low concentrate level to high. It is the reason drinking seawater can kill you. The seawater in your stomach draws water out of your body trying to dilute the high concentrate of salt, eventually leading to dehydration and death.
Reverse osmosis (RO) is the process of flowing from high concentrate to low. Pressurized water is forced through a very fine membrane while discharging excess water and concentrate (pollutants in this case). Reverse osmosis systems are usually constructed of several stages, including a pre-filter, semi-permeable membrane, pressurized storage tank to hold the treated water, and carbon adsorption post-filter.
Reverse osmosis system (courtesy of Watts)
Reverse osmosis systems do an excellent job of removing all forms of pathogens as well as chemical impurities. However, they require high water pressure (typically > 40 psi), and therefore may necessitate the use of an electric pressure-boost pump in some homes. They also waste a great deal of water, turning out only 5–10 percent of the incoming water. The remaining water is flushed away with the pollutant. To create 1 gallon of purified water might take 8 to 18 gallons of incoming water.75 Finally, reverse osmosis systems require periodic maintenance, including replacing the pre- and post-filters annually and the membrane every few years.
Be forewarned that there are two very vocal groups of water filter marketeers—those who sell distillation devices, and those who sell reverse osmosis systems. Salesmen for distillation devices will claim that reverse osmosis removes important minerals. Likewise, those selling reverse osmosis systems will claim that distillation causes the water to taste flat. Both salesmen will claim that the competing technique doesn't remove contaminants as well as the one they are selling.
There is a little bit of truth in both arguments. Yes, distilled water can taste flat. And yes, reverse osmosis does remove minerals. But both issues are not really problematic. The flat taste can be eliminated by aerating the water—simply pour the water back and forth between containers and allow it to sit for a few hours. Also, the loss of minerals from reverse osmosis is not usually considered a health concern since Americans get most of their minerals from the foods they eat. The good news is that both types of systems filter water exceptionally well, removing all forms of pathogens and many chemical contaminants.
It is also possible to disinfect water using ultraviolet (UV) light. This treatment method has been used for years by large water treatment facilities, but it has only recently been available for the home user, traveler, or hiker. Two units are widely available: Meridian Design's AquaStar and Hydro-photon's SteriPEN. The AquaStar includes a heavy plastic bottle with an enclosed UV light source. The SteriPEN is a small, portable UV light pen used to stir water in a glass or bottle. Both claim to have been independently certified to meet the EPA Guide Standard.76
Courtesy of Hydro-Photon
Using either of the portable UV devices is quick and easy (taking only thirty–eighty seconds) and has been shown to be very effective against all types of pathogens. The UV light effectively disrupts the microbes’ DNA, preventing them from multiplying. Unlike chemical disinfectants, ultraviolet light is also effective at neutralizing protozoa such as Giardia and Cryptosporidium.77
However, neither device will remove impurities (e.g., dirt, particulates, chemicals) or help improve the taste of the water. There are also some concerns over the effectiveness of the devices in turbid water. For example, independent testing showed that the SteriPen did a poor job of purifying muddy water.78 For this reason, it is recommended that water be clarified prior to using a UV light purification device.
Those limitations aside, portable UV purifiers do offer a convenient method of purifying small quantities of water.
When no other methods are available, sunlight can be used to decontaminate water. This method of solar water disinfection (a.k.a., SODIS) takes advantage of the ultraviolet emission of the sun to kill waterborne microorganisms and is used in developing countries around the world.79
The SODIS method is easy to follow:
1. Wash the bottles thoroughly with soap and water.
2. If necessary, perform basic filtering to clarify the water.
3. Fill the bottles with water, and close the lids.
SODIS (courtesy of EAWAG)
4. Expose the filled bottles to direct sunlight for a minimum period of time.
5. Drink directly from the bottles, or pour the water into a clean cup.
The method is simple, however, you must use colorless, transparent, polyethylene terephthalate (PET) bottles no larger than 2 liters in size. Glass and other plastic materials can block the ultraviolet light needed to purify the water. Fortunately, most convenience-sized beverage bottles sold in the United States are made of PET materials.80
At a water temperature of 86°F, a minimum of six hours of direct, summer sunlight is needed for mid-latitude regions. Colder water requires longer, as do cloudy conditions. For example, on days that are 50–100 percent overcast, water decontamination requires a full two days of exposure.79
The SODIS method has been proven to reduce cases of diarrhea caused from some waterborne pathogens. However, it has not been shown to kill all waterborne pathogens. Also, it is not clear that SODIS will kill trace contamination on the threads of the bottle. For these reasons, it should be considered a last resort for water decontamination.
With all the advantages and disadvantages in hand, it becomes easier to select the optimal purification methods. Remember the two goals of purification: remove debris/particulates, and neutralize the pathogens. Given the methods discussed, to remove anything requires either filtration, distillation, or reverse osmosis. Fortunately these methods also improve the taste of water—something that can be important to many finicky drinkers. Refer to Table 3-3 for a comparison of water purification methods.
For general in-home use, an EPA-certified purifier, water distiller, or reverse osmosis system are all perfectly adequate. However, for disaster preparedness, a certified purifier is preferred over a distiller or a reverse osmosis system. This preference is because the purifier doesn't require electricity like distillation, and doesn't waste water like reverse osmosis. Table 3-4 summarizes the benefits and drawbacks of the three preferred POU and POE methods.
When it comes to portable systems, the only single-step solution that removes particles and neutralizes pathogens is a certified purifier. If you are willing to combine two methods, then several other options exist. For example, combining boiling, UV light, or the MIOX with a standard filter can neutralize pathogens, clarify the water, and make it more palatable.
When selecting a water filter, you should know that all water filters are not created equal. Many manufacturers promise “clean water” using vague claims about their products that are impossible to fully understand. When it comes to filters, it is definitely let the buyer beware. Don't assume anything. When buying a used car, you want to see the Carfax report to verify that things are as the seller claims. In the case of water filters, you need to see the impurity removal test data.
Selecting a water filter is akin to purchasing a used car—let the buyer beware!
If you can't find independent technical data showing how well the filter removes a certain type of contaminant, then you should assume that the filter falls short in that area. Remember, manufacturers want to convince you that their product is the best, so if they are not showing you the data then they likely have something to hide. Table 3-5 lists several misleading terms that you may see in water filter advertisements. In general, these claims indicate nothing about the capabilities of the filter.
Table 3-5 Making Sense of Filter Claims
Claim |
Meaning |
Registered with the EPA |
All filters that use a chemical disinfectant must be registered. It is not an indication of their effectiveness. |
Tested/Approved by the EPA |
The EPA does not test or approve filters. |
Nominal pore size of x microns |
“Nominal size” indicates the average pore size, not absolute. The filter could have pores significantly larger than the average size—making it ineffective at filtering smaller pathogens. |
Effective against Giardia, etc. |
Claiming to be effective without providing specific data is meaningless. |
There is also a great deal of confusion over the difference between filters and purifiers. As discussed previously, for a product to be described as a water purifier, it must be highly effective at removing, killing, or inactivating all forms of pathogens.81 The word “filter” is a broader term describing any device used to remove contaminants, regardless of its effectiveness.
In reality, there are very few filters that can be classified as true water purifiers. This is largely due to the difficulty in filtering out viruses. Two exceptions worth noting are the General Ecology Seagull IV series (sink mount) and the General Ecology First Need (portable). These purifying systems have been independently certified to meet the EPA Guide Standard without the use of chemical purification. Other filters may outperform these purifiers for specific contaminants, in particular Cryptosporidium, but the noted models offer a unique one-step solution to purifying water without the use of chemicals, UV light, or boiling. General Ecology also offers an emergency preparedness conversion kit (EPK) that converts their Seagull IV POU purifier to a portable pump-driven system.
Water purifiers (courtesy of General Ecology)
Filter certification can also be confusing because there are three sources of official water filter certification, all of which are accredited by the American National Standards Institute (ANSI):
• National Sanitation Foundation International (NSF)82
• Underwriters Laboratories (UL)83
• Water Quality Association (WQA)84
Each of the organizations has its own certification program (e.g., WQA Gold Seal, UL Water Quality Mark), but all require testing to the same ANSI/NSF standards.
WQA Gold Seal
Standards set the requirements for each the four different purification methods: filtering, UV light, reverse osmosis, and distillation. These standards require that careful testing verifies that the filter reduces specific contaminants by a certain amount (e.g., 99.9% removed). Construction, product labels, and sales literature are also inspected. Periodic re-certification and inspection are required. The key ANSI/NSF standards relating to point-of-use (POU) water filters are listed below:85
• Standard 42: Drinking Water Treatment Units—Aesthetic Effects
• Standard 53: Drinking Water Treatment Units—Health Effects
• Standard 55: Ultraviolet Microbiological Water Treatment Systems
• Standard 58: Reverse Osmosis Drinking Water Treatment Systems
• Standard 62: Drinking Water Distillation Systems
To verify that a product was tested by an official lab, go to the NSF, WQA, or UL website and search their database of certified products. Testing by any of these three accredited organizations is expensive. As a result, many companies elect to have independent testing done by universities or other outside labs. Accordingly, they may state that their product is “tested to the NSF/ANSI standards by an independent lab.” Most independent test labs are reputable, and the results are considered accurate. Regardless of who does the testing, the results should be published and available for the customer's review.
Given the list of ANSI/NSF standards, it would seem that selecting a POU water filter would be as easy as finding one that is certified to Standards 42 and 53. Or, if using alternative technologies (e.g., ultraviolet light, reverse osmosis, distillation), you would ensure that the product meets the associated standard (i.e., Standards 55, 58, or 62 respectively). In general, this selection criteria is sound. However, there is one important point to note: a significant shortcoming of Standard 53 is that it has no criteria to check effectiveness against bacteria or viruses. Broadening of the standard to include bacteria and viruses has been discussed for many years. Until that effort is complete, Standard 53 is of limited value in selecting a filter system.
NSF/ANSI standards do not set criteria for bacteria or virus removal.
True purifiers are certified to the EPA Guide Standard.
The NSF has recognized this shortcoming and has been working on standards that address all pathogens.86 As a stop gap, NSF currently tests to Protocol P231, which aligns with the EPA Guide Standard.
If you decide to purchase a water purifier, find one that is certified to the EPA Guide Standard. If the retailer does not clearly advertise this qualification, rest assured the product is not certified. Certification is like winning an Olympic gold medal; you are going to display it for everyone to see.
Filter elements must be changed periodically, or the filter will lose its effectiveness. The element can become clogged with debris (usually indicated by reduced water flow), or the surface of the filter can become saturated, leading to reduced performance.87 The time between filter changes is dependent on the condition of the water being filtered. If you are pumping water directly from streams or lakes, you will need more frequent filter changes than if you are filtering tap water.
Portable filters should be cleaned after each use.
Follow the manufacturer's recommendations whenever possible. Beyond that, change the filter anytime you notice the flow rate has decreased or the water begins to have an unpleasant taste or odor. Regardless of performance, change the water filter element at least annually.
Portable filters that are used infrequently should be cleaned after each use. This will prevent bacterial growth. A simple way to do this is cycle a weak bleach solution (i.e., 1 tbsp bleach into 1 gallon of water) through the unit. Then allow the filter to air dry.
The fundamental goal of your water plan should be to have access to enough potable and non-potable water to see your family through a two-week disaster. Given the resources necessary to store hundreds of gallons of water, it is likely that in some situations you may find yourself in need of more water than you have stored.
In the best case, you can simply turn on the tap. The water may require purification before drinking, but at least you won't have to forage for water. In the worst case, however, your local water service may have been cut off due to excessive contamination, shortages, or sabotage.
When tap water is no longer available, you will need to locate alternate water sources. There are likely many such sources around you.
Alternative Water Sources
Hot water heater
Water pipes
Toilet
Waterbed
Swimming pool
River, lake, or spring
Your hot water heater is an excellent source of potable water. Many units are 75 gallons or larger in size, giving you a sizable emergency stockpile. Water can be drained out the bottom of the tank through the built-in spigot. The five-step process to drain the tank is straightforward. Like all preparation steps, however, you need to practice on your particular water heater before a crisis hits. Don't assume that you can do it and then find yourself in an “oh, crap” moment later.
Draining Hot Water Heater
1. Turn off power or gas to the water heater.
2. Turn off the incoming water supply.
3. Attach one end of a hose to the spigot, and put the other end into a bucket below the level of the spigot.
4. Open the pressure relief valve near the top of the tank, or turn on a hot water faucet in the home.
5. Open the spigot and collect the water in the bucket. Careful, it is hot!
When water is shut off by your local water authority, it may still be possible to drain the water in your home's pipes for potable water needs. However, to have access to the water in your pipes, you must first prevent it from draining back out of your home. This is done by installing an anti-siphon water valve on your incoming main water line. The anti-siphon valve automatically closes when the water pressure gets too low, thereby keeping the water safely stored in your home's pipes.
Draining Water Pipes
1. Turn off the incoming water main.
2. One by one, turn on all of the taps at the highest elevation, collecting the small amount of water that comes out of each. Leave the taps open.
3. Turn on the taps at the lowest elevation, collecting the water that comes out—this might take several minutes.
4. Once all of the taps stop outputting water, close them.
Personal aside: I was able to recover just over two gallons of water from the pipes in my two-story home. Cut off the water main, and try this water recovery process in your own house to have a better idea of the expected yield.
The water from the toilet tanks (not bowls) can be used for drinking, but you should purify it first. Purification is needed because bacteria and rust can collect in the tank. Use a portable filter to retrieve the water, or simply scoop the water out with a cup and soak up any remaining water at the bottom with a rag or sponge.
Depending on your particular model of toilet, this could yield anywhere from 2 to 7 gallons of water per toilet.
If you have a waterbed or swimming pool, it can act as an excellent secondary source of water. However, according to the NSF, the water from a waterbed or swimming pool should only be used for non-potable needs.88 High levels of chemicals and/or organic contaminants may be present, and no method has been proven effective at making this water completely safe.
The water from rivers, lakes, or other fresh water sources can be used directly for non-potable needs, or for potable needs (e.g., drinking, bathing) if purified first. If the water contains visible particulates, such as dirt or twigs, use a coffee filter or clean bandana to do a cursory filter before purification. Regardless of how clear the water may appear to be, assume all natural water sources are contaminated. If the water is very shallow, use a rag or sponge to soak it up.
Sea water should not be used for potable needs unless purified with a desalination device. Never drink brackish water since it will dehydrate you, and can lead to death.
When you have exhausted all known water sources, it may be necessary to extract water from the environment around you. Extraction techniques are referred to as natural collection. Collection of this sort should be considered a last resort. Despite what you may have read in various survival manuals, natural collection is very difficult and requires skill, materials, and patience.
Natural Collection Methods
Rain collection
Dew collection
Transpiration
Solar still
Don't make the mistake of relying on natural collection without having spent the necessary time and energy learning how to do the extraction effectively. There are very few people, for example, who can build a solar still and get more water from it than they put out in sweat building it. Before relying on any natural water collection method, practice it ahead of time! Don't wait until you are dying of dehydration to figure out that you don't know what you are doing.
Don't rely on natural collection methods. Treat them as a last resort.
Rain water can be an excellent source of natural water. The obvious (and significant) disadvantage of collecting rain water is that rainfall is unpredictable. Also, given that in most places it usually rains one inch or less with each rainfall, you will need a large surface area to collect enough water. A child's inflatable swimming pool works well. A six-foot diameter pool collects about 18 gallons of water if it rains one inch.89
A kid's inflatable swimming pool makes a great rain collector.
An alternative is to use a clean, waterproof tarp tied up into a mild “V” shape, sloping downward into a large container. With a 10 ft × 12 ft. tarp, you can collect up to about 70 gallons of water from a one-inch rainfall.89 Be sure to secure your tarp so that it won't be blown down by heavy winds. The idea is to face the tarp into the wind, allowing rain to blow onto the surface, down the channel, and into your water storage container.
Another good method of collecting rainwater is to place buckets (or rain barrels) under your home's gutter down-spouts. The large surface area of your roof will yield significant water. People have been doing this for years to collect water for use in their gardens, as well as prevent flooding of their yards.
A final, albeit less effective, option for collecting rain water is to hang bed sheets outside your windows. Let them get drenched in the rain, and then bring the sheets inside and ring the water out into a container. Repeat for as long as the rain continues.
All rain water should be purified by one of the recommended methods before drinking.
Great American Rain Barrel
In heavily vegetated areas, dew can be collected off plants early in the morning or immediately after a rainfall. This can be done by dragging absorbent rags across the surface of plants. Once the rags become saturated, wring them out into buckets. Continue the process until the yield starts to decrease as temperatures rise.
Dew collection can yield significant water with nothing more than a rag and a bucket.
The advantages of dew collection are that it requires only minimal supplies and can yield fairly good results even in the wilderness. The two drawbacks are that the collection process can be mildly arduous, and once again water must be purified before drinking. The method is also not effective in areas with limited vegetation.
Personal aside: Following a rainfall, I was able to collect 12 cups of water in one hour using only a sturdy paper towel and a small bucket—a significant yield.
Transpiration water collection requires large, clear bags and twine.
Transpiration bags use evaporation and condensation to collect water. Large clear plastic bags are secured over the green foliage of non-poisonous plants. Plants with large root systems work best. The opening of the bag is tied off to make it as airtight as possible. Using a cloth or paper as a gasket in the mouth of the bag will also help. The bag creates a greenhouse effect causing the plant to release water vapor. The vapor then condenses on the inner surface and pools in the bottom corner of the bag (see illustration).
The amount of water released through transpiration varies by temperature (as temperature rises, yields increase), relative humidity (as humidity rises, yields drop), plant type, and soil moisture. The biggest advantage of using transpiration bags is that they can be placed with very little energy, allowing for many bags to be used in parallel. However, practical yields are often minimal (perhaps only a cup per bag per day, depending on conditions). Also, be aware that transpiration bags can kill the plants.
A modest secondary benefit can be had by wiping dew from the outside of transpiration bags during the early morning hours.
Transpiration
The solar still is a well known natural water collection method also based on the greenhouse effect. Two simple models are the single-sloped box still and the pit still (see illustration on next page). With the single-sloped still, a sealed box is constructed with a dark insulator material lining the bottom, a sloped clear glass or plastic barrier on top, and a way of introducing and removing the contaminated and distilled water.
The pit solar still is the type you will find in most survival manuals. It consists of a large hole in the ground, perhaps 3 feet across, covered with a clear plastic barrier. A collection cup is placed in the center of the pit, and a water source (e.g., shredded vegetation, urine, brackish water) around the cup. A rock is put on top of the plastic to form an inverse apex centered over the cup. Rubber tubing can be used to drink water from the cup so as not to disturb the still.
Solar stills—pit style and single-sloped box
Both types of stills operate in a very similar manner. Solar energy heats the ground or black background. Moisture inside the greenhouse evaporates, rises, and condenses on the underside of the clear barrier. The solar- distilled water then runs down the slope and drips into a collection channel or cup.
One significant advantage of the solar distillation process over other natural collection methods is that the water recovered does not require purification. Plants, sea water, and even urine can be used as the originating source of water. All will ultimately produce clean, drinkable water.
If you think solar stills are easy to make work, you've never built one.
However, there are three notable problems with the solar still. First, it requires materials (plastic, collection cup, and tubing) and a shovel for digging the hole. The still also takes significant energy to set up. Finally, it is very difficult to make work effectively. Experts who have evaluated the effectiveness of the solar still suggest that many things can go wrong—causing it to provide very little if any water. Problems can include failing to get the plastic sufficiently tight, wind disturbance, insufficient transparency of plastic, improper angle to the sun, and a host of other things.90 Some experts swear by solar stills. Others will warn you away.
Store, or have access to, enough potable water to maintain your family for fourteen days, assuming 2 gallons per day per person.
Have access to enough non-potable water for at least one toilet flush per person per day for fourteen days. Water quantity varies based on toilet model.
Hygiene is critically important during a disaster because falling ill can leave you weak and unable to handle the situation's hardships.
Store potable water in FDA-approved containers out of light and away from chemicals or gasoline.
If keeping a permanent stockpile, rotate the water every six months or treat with a water preserver.
Water pre-treatment is usually unnecessary for tap water.
Pathogens found in water include protozoa, bacteria, and viruses. To purify the water, you must remove, kill, or neutralize the pathogens.
Recommended home POU or POE purifying methods include: certified purifiers, distillers, and reverse osmosis systems.
Recommended portable purifying methods include: certified purifiers, or combining filtering with boiling, UV light, or chemical treatment.
Use secondary sources as necessary, including your home's hot water heater, water in house pipes or commode tanks, swimming pool, waterbed, and rivers or lakes.
Do not try to purify seawater without a desalination device.
Depend on natural collection methods only as a last resort. Natural methods include rain collection, dew collection, transpiration, and solar stills.
Test your water collection methods before an emergency.
Water Storage
a. Large water containers to allow for 28 gallons of potable water per person stored in FDA approved containers—for example, 55-gallon water storage barrels with pump, Super Tankers, Aquatank water bags
b. Two sets of smaller water containers for retrieving and transporting water (one set for potable water, one set for non-potable water)—for example, plastic jerry cans, 2-liter bottles, five-gallon buckets, WaterCubes, dromedary bags
Water retrieval
a. Garden hose and bucket for draining the hot water heater
Chemical disinfectant for preparing containers, treating water, and cleaning surfaces.
a. Jug of household bleach, dropper
A home POU or POE water purification system
a. A purifier that meets the EPA Guide Standard, or
b. Water distiller, or
c. Reverse osmosis system
A portable water purifier
a. A purifier that meets the EPA Guide Standard, or
b. UV light, or
c. MIOX device
Supplies to stay clean
a. Adequate supply of hand soap, alcohol-based hand sanitizer, and hand/body wipes
b. Supply of large plastic bags and twist ties
Sanitation needs
a. Access to enough non-potable water for at least one toilet flush per person per day, or
b. A potty bucket, plastic bags, and treatment chemicals, or
c. A self-contained composting toilet
