Locating Safe Drinking Water

After a disaster, it is possible that water supplies will be temporarily cut off or become contaminated. Because you must have water to survive, it is important to know how to locate and purify drinking water to make it safe.

Water Sources

In the home. Melt ice cubes, and use water from the hot-water tank, the toilet tank (not the bowl) and water pipes.

Hot water tank. Turn off the power that heats it, and let the tank cool. Then place a container underneath and open the drain valve at the bottom of the tank. Don't turn the tank on again until water services are restored.

Toilet tank. The water in the tank (not the bowl) is safe to drink unless chemical treatments have been added.

Water pipes. Release air pressure into the plumbing system by turning on the highest faucet in the house. Then drain the water from the lowest faucet.

Outside the home. Rain water, spring water, and water from streams, river, lakes, and coiled garden hoses can be used after it is purified.

Water Beds

Avoid water from water beds as a source for drinking water. Pesticidal chemicals are in the plastic casing of the bed and chemicals have probably been added to the water to prevent the growth of algae, fungi, and bacteria. The water is safe only for hand-washing and laundering.

Purifying Water

Boiling and chemical sterilization are two ways to purify water.

Any water that is obtained from sources outside the home or water that does not appear clear should be sterilized. Non-sterilized water may be contaminated with the parasite Giardia.

Straining water. Strain water containing sediment or floating material through a cloth or paper filter before beginning the purification process.

  • Heat sterilization. Boiling water is the preferred method of purification because disease-causing- microorganisms cannot survive the intense heat. Bring water to a rolling boil for 1 minute. Pour the water back and forth from one clean container to another to improve the taste. Adding a pinch of salt could also help.

  • Chemical sterilization. In some situations, boiling may not be an option. The alternative is to treat the water chemically. Plain household chlorine bleach may be used. Be sure the label states that hypochlorite is the only active ingredient. Bleach containing soap or fragrances is not acceptable. With an eye dropper, add 8 drops of bleach per gallon of water (16 if the water is cloudy), stir and let stand. After 30 minutes the water should taste and smell of chlorine. At this time it can be used. If the taste and smell (and appearance in the case of cloudy water) has not changed, add another dose and let stand. If after one half hour the water does not have a chlorine smell, do not use it.


Store the water in a clean and sanitary glass or plastic container. Plastic containers are good because they are lightweight and unbreakable. Metal containers should be considered as a last resort because they may corrode and give water an unpleasant taste.

Water that local officials report has been contaminated with toxic chemicals or radioactive materials cannot be purified using home decontamination methods.

Facts About Water

Water is the single most abundant substance in the human body, making up to 60 percent of an adult's weight and up to 80 percent of an infant's weight. A person can live several days without food, but just a few days without water. It is second only to air in importance to life.

Because water is so important to human survival, never ration it. Drink at least 2 quarts per day, as long as supplies last, and look for alternative sources.