Simple Water Purification Methods

Safe, clean drinking water is essential to human life and health. Millions of people die each year from consuming contaminated water. Fortunately, several simple and inexpensive methods for water purification are available. Note, however, that many of these purification methods will kill microbes that cause disease, but will not remove heavy metals, pesticides, hydrocarbons and other dangerous chemical contaminants. For best results, use a combination of purification methods to produce safe drinking water.

Boiling

• Boiling water is the safest way to kill microbes.

  Boiling is a safe and easy method of killing bacteria and other pathogens in water. Simply boil the water for 10 minutes, and let it cool before drinking. When energy to boil the water is available, and chemical contamination is not a concern, boiling is the most reliable water-purification method. Pouring the water back and forth between two vessels will add oxygen to the water, making it taste better. Allow any sediment to settle to the bottom before drinking or pouring.

Bleach

• Adding regular bleach (with no scent or other additives) to water will prevent the growth of microorganisms and kill any pathogens that are present. Simply add two to four drops of bleach per quart of water --- two drops if the water is clear, or four drops if the water is cloudy --- and wait 30 minutes before drinking. Pouring the water back and forth between two containers will help to spread the bleach throughout the water.

Iodine

• Iodine is another effective chemical treatment for microbes in water. However, some people are allergic to iodine. Also, this method is inappropriate for pregnant women, people with thyroid problems and people who are taking lithium. To purify water, use a 2-percent tincture of iodine, which is available in drugstores. Add five drops per quart of water, or 10 drops if the water is cloudy. Again, pouring the water back and forth will mix the iodine thoroughly, and make the water taste better. Adding a little vitamin C after bleach or iodine treatment will also improve the taste of the water.

Solar Disinfection

• The sun's ultraviolet rays can disinfect water in plastic bottles.

  The sun's ultraviolet rays and heat will kill pathogens in water. Fill clean, clear plastic bottles with water and set them out in the hot sun (preferably atop a black cloth, which helps to absorb the sun's heat) for at least six hours. If the sky is overcast, disinfection may take up to two days. This purification method is common in certain villages in Tanzania.

Filtration

• If the water is cloudy, it is a good idea to filter it through a clean cotton cloth before attempting the preceding purification methods. Alternatively, you can make a slow sand filter using a five-gallon bucket, cloth, gravel and sand. Punch holes in the bottom of the bucket, and fill it partially with gravel. Put a cloth on top of the gravel and add a few inches of fine sand. Put another cloth on top of the sand. Pour water into the bucket; the water that comes out will be free of most biological contaminants and suspended particles.

Distillation

• Distillation involves boiling water and collecting the resulting water vapor as it condenses. Distilling water will remove microbes, chemicals, salts, dirt and radioactive dust (if present). The New Jersey Office of Emergency Management recommends distilling water by filling a clean pot halfway with water, and tying a cup to the pot lid's handle so that the cup will hang upright when the lid is upside-down over the pot. Boil the water for 20 minutes; the water vapor will condense on the lid and fill the cup.