Water in an Emergency
Drinkable water is absolutely essential for maintaining health. It is also vital for cooking, personal hygiene, sanitation, cleaning wounds, sprouting seeds and reconstituting dehydrated foods and drinks.

Because water is so essential for survival, in an emergency it is wise to have both a portable and a non-portable (e.g., 55-gallon barrels) supply of drinking water. It is also important to have a way to treat or acquire water for your continuing needs in case an emergency lasts longer than expected.

portable water

Preparatory Water Storage

In preparation for an emergency it is important to have water already stored.


Portable water is easily carried in an Emergency Kit or can be put into a vehicle (e.g., boxed water). Portable water generally weighs less than 40 pounds (about 5 gallons) per container. Three gallons of water (enough to last for three days) should be available for each person.


Non-portable (permanent) water is stored in large containers, such as a 55-gallon barrel. These large containers are considered permanent storage because they can be extremely heavy and are not easy to move. A 55-gallon barrel of water weighs about 470 pounds.

For your permanent home water storage supply, store approximately 14 gallons per person for a two week period. A 55-gallon barrel will supply a family of 4 for 14 days. When an emergency hits, storing both portable and permanent supplies of water is the wisest plan. If you need to replenish this supply it is best to start with the cleanest, salt-free, and least polluted water that you are able to obtain.

Cold running river water is preferred to warm stagnant water. There are various methods to treat water, but remember that no method of treating is perfect for obtaining safe water so combining methods is often the best solution.

Disinfecting Water in and Emergency

There are two primary methods to convert "raw" undrinkable water into safe, potable (drinkable) water: Disinfection and Separation.

Each method has its advantages and disadvantages. Combining these two methods is the best way to achieve safe drinking water. The five most commonly used ways to disinfect and separate water (make it free from disease-causing microorganisms) are:

  1. Boiling
  2. Adding a Chemical (water purifier tablets, chemicals, or silver)
  3. Using Ultraviolet Light
  4. Microfiltration
  5. Distillation

In this post we will discuss the first three methods known as Disinfection.

Remember to use only water that has been properly disinfected for cooking (including drinks) or for brushing your teeth.

boiling water


Historically, boiling water has been the most common way to disinfect water from microorganisms. Boiling water will kill most types of disease-causing organisms that may be present. If the water is cloudy, filter it through clean cloths or allow it to settle, and draw off the clear water for boiling.

Boil the water for one minute, let it cool, and store it in clean containers with covers. Because the boiling point is lower at higher altitudes, EPA policy statements recommend that individuals at elevations above two kilometers (6562 feet) boil their water for three minutes as a precaution.

There are drawbacks to boiling water.

  • First, it can require a lot of fuel and cooking equipment.
  • Second, you must consider the long cool-down period.
  • Third, the water will still have particulate substances in it, so you should use a clean handkerchief to filter it before drinking.
  • Last, boiling water does not eliminate pollutants, poor taste or foul odors.

A helpful hint to improve the taste of boiled water is to transfer it from one container to another several times while boiling.


Chemical disinfectants are used to kill microbes in the water. The primary chemicals used for disinfecting water are chlorine dioxide, chlorine, and iodine. These chemicals are lightweight, low-cost and relatively easy to use. Another way to disinfect water is using silver. We'll conduct a brief overview of each:

1. Chlorine Dioxide

Chlorine dioxide kills viruses, bacteria and protozoa. It has been used for years to treat municipal water supplies in Europe. It is believed to be better than iodine because it kills more microorganisms (including the common Cryptosporidium protozoa). There are also fewer concerns with long term exposure/allergies and it is more effective over a wider range of temperatures. It is more effective as a disinfectant than chlorine in most circumstances against water borne pathogenic microbes such as viruses, bacteria and protozoa – including the cysts of Giardia and the oocysts of Cryptosporidium. Chlorine dioxide is available in a tablet form, or can be created as needed using a device such as a Miox®

chlorine bleach

2. Chlorine bleach

The EPA states the following: “If you can't boil water, you can disinfect it using household bleach. Bleach will kill some, but not all, types of disease-causing organisms that may be in the water.

If the water is cloudy, filter it through clean cloths or allow it to settle, and draw off the clear water for disinfection. Add 1/8 teaspoon (or 8 drops) of regular, unscented, liquid household bleach for each gallon of water, stir it well and let it stand for 30 minutes before you use it. Store disinfected water in clean containers with covers.

Most U.S. cities have moved from Chlorine treatment of water to filtration and Chlorine Dioxide over the last 15 years. This is because protozoa have an egg-like cyst form. It takes time for chemicals to eat through the cyst shell, but the protozoa can be readily removed with micro-filtration.

3. Iodine

Iodine has been found to be very effective against viruses, bacteria, and protozoa with the exception of cryptosporidium.

  • Using iodine has some drawbacks.
  • The colder the water you wish to disinfect, the more time is required for disinfecting.
  • Because iodine is absorbed into dirt and debris, which is found in water, its purification dosage varies.
  • Pregnant women and people with thyroid conditions should not drink water purified with iodine.
  • Additionally, iodine is a short-term water-purification solution and should not be used regularly for more than three months.

Iodine does not change the clarity of water but it does change its taste. Many people do not enjoy the taste of iodine. This taste can be improved by adding a sugar-based drink or juice mix.

4. Silver

Throughout the centuries, people in many countries have used pure silver to disinfect water. Silver is a natural anti-microbial agent and has been demonstrated to kill bacteria and viruses; however, it has not been shown to kill all protozoa.

Today there is an improved method of creating silver as a safe antimicrobial agent without the worry of argyria, a condition in which the skin can turn a blue/grey. Silver has a history of being a proven method to act against a wide range of yeasts, bacteria and viruses. It also can be used in various emergency situations.

uv light


Ultraviolet light requires electricity, so it was usually used only as a home water treatment method in the past.

There now is a portable water purifier that uses ultraviolet (UV) light to destroy waterborne microbes. It purifies clear water by destroying viruses, bacteria and protozoa-including Giardia and Cryptosporidium.

UV light kills Cryptosporidium in 32 oz. of clear water in 90 seconds, while chemicals take four hours to do the job. UV lighting literally sterilizes the microorganisms rendering them ineffective in making one sick. UV lighting adds no chemicals which change water’s taste.

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