Hurricanes and tropical storms can contaminate drinking water supplies. Besides having a bad odor and taste, unsafe water can contain microorganisms such as bacteria and parasites that cause diseases such as dysentery, cholera, typhoid and hepatitis. Water of questionable quality should be treated before use.

To treat water, the American Red Cross recommends that hurricane survivors:

  • Filter the water using a piece of cloth or coffee filter to remove solid particles.
  • Bring the water to a rolling boil for about one full minute.
  • Cool the water at least 30 minutes so it can be treated for chlorine.
  • Add 16 drops of liquid chlorine bleach per gallon of water, or 8 drops per 2-liter bottle of water. Stir to mix. Sodium hypochlorite of the concentration of 5.25 percent to 6 percent should be the only active ingredient in the bleach. There should not be any added soap or fragrances. A major bleach manufacturer has also added sodium hydroxide as an active ingredient, which it states does not pose a health risk for water treatment.
  • Let the water stand for 30 minutes.
  • If the water smells of chlorine, it can be used. If it does not smell of chlorine, add 16 more drops of chlorine bleach per gallon of water (or 8 drops per 2-liter bottle of water), let stand 30 minutes and smell it again. If it smells of chlorine, you can use it. If it does not smell of chlorine, discard it and find another source of water.

According to the Red Cross, if local public health department information differs from this advice, the local information should prevail.