Whether a natural disaster leaves your home without utilities, war disrupts your water lines or a breakdown of civil services forces you into self-reliance, the time for preparation is now. Globally, people suffer when the sources of support they rely upon fail unexpectedly. Because no government or private agency is capable of preventing disruption of services in extreme circumstances, there is a good chance that your source of sterilized drinking water could fail. For this reason, knowing how to purify water at home is an essential survival skill.
Gather water from your natural environment. First, assemble all remaining sources of sterilized water. In the home, this includes melting ice cubes, draining water heaters, collecting water from toilet tanks and using bottled water. (Reference 1) Remember that water found in toilet bowls, washbasins and idle water hoses is not sanitary. Next, scout for external sources of water. Possible locations include wells, aqueducts, lakes, ponds and streams. Avoid water that is stagnant, cloudy or has an odor. Clear water drawn from a running source is considered best.
Create a basic purification filter if the only available water source is contaminated with dirt particles or other debris. Find a barrel, bucket or drum that will hold at least 10 gallons. Drill a hole in the lowest point of the container’s side and cork the hole. Place a perforated false bottom inside the container several inches above the actual bottom. Cover the perforated bottom with cloth, ensuring it stretches across the entire space. Overlay the cloth with a couple inches of fine gravel. Fill the container with three layers of charcoal and clean, white sand, alternating between charcoal and sand. Top the layers of charcoal and sand with another layer of fine gravel. Insert a perforated top several inches below the container’s upper rim. Pour the contaminated water into your filter and remove the cork at its bottom to receive the filtered water. Continue filtering the water until it is clear. Activated charcoal helps to remove pesticides, benzene, some metals and radon. Replace the layers of charcoal and sand when the filter becomes inefficient. (Reference 2)
Boil the filtered water. Even though filtered water may be crystal-clear, it can still contain viruses, microscopic parasites like Giardia lamblia and Cryptosporidium and bacteria such as Escherichia coli, Campylobacter and Shigella. Boiling is a highly effective method of purifying water because it kills these disease-causing microorganisms. A stove or microwave oven is the simplest way to boil water if you have electricity. Should electricity be unavailable, build a frame that holds a sheet of metal over an open fire. The metal will act as a hotplate on which to place your pot or kettle. This plate will also act as a griddle for cooking food. Add salt to reduce the water’s boiling point and speed the process. Bring the water to a rolling boil for at least one minute and then allow the water to cool. Store the purified water in clean, sealed containers.
Apply chlorine bleach whenever boiling water is impractical or impossible. Although not as effective as boiling, chemical treatment does provide protection against many harmful microorganisms. However, its protection against Giardia and Cryptosporidium is limited. Non-chlorine household bleach will not purify water. Check the bleach’s label for its chlorine content. If the content is 1 percent, apply 40 drops to every gallon of untreated water. If the content is 4 to 6 percent, apply 8 drops per gallon. If the content is 7 to 10 percent, apply 4 drops per gallon. Allow the water to stand, covered, for at least 30 minutes before consumption. Water that has been filtered and boiled should also be chemically treated if you plan to store it for any length of time.
Use an alternate source of purification. If you have no chlorine bleach and cannot boil the water, find a first aid kit that contains iodine drops. Use 2 drops for every quart of water. Increase this to 10 drops if the water is cloudy. Similar purification chemicals are found at most drug and sporting goods stores. These include granular calcium hypochlorite, chlorine tablets, iodine tablets and potassium permanganate. Follow all manufacturer instructions when using these products.